Patent Application: US-201615283404-A

Abstract:
we disclose growth hormone fusion proteins that have increased in vivo stability and activity ; nucleic acid molecules encoding said proteins and methods of treatment of growth hormone related diseases that would benefit from growth hormone agonists or antagonists .

Description:
according to an aspect of the invention there is provided a fusion protein comprising growth hormone or a modified growth hormone linked either directly or indirectly to a polypeptide comprising the amino acid sequence of a growth hormone receptor polypeptide wherein said receptor polypeptide is modified by addition , deletion or substitution of at least one amino acid residue wherein said receptor polypeptide substantially lacks growth hormone binding activity or has reduced growth hormone binding activity . in a preferred embodiment of the invention said fusion protein comprises or consists of the extracellular binding domain of growth hormone receptor ; preferably human growth hormone receptor . in a preferred embodiment of the invention the fusion protein is modified in the growth hormone binding domain of said extracellular binding domain . in a preferred embodiment of the invention said modification is one or more of the amino acid sequences selected from the group consisting of : w169 , r43 , e44 , i103 , w104 , 1105 , p106 , i164 and d165 as represented in fig1 a ( seq id no : 1 ). in a preferred embodiment of the invention said modification comprises or consists of deletion of amino acid residue tryptophan 104 of the amino acid sequence represented in fig1 a ( seq id no : 1 ). in a preferred embodiment of the invention said amino acid residue tryptophan 104 is substituted for one or more amino acid residues ; preferably tryptophan 104 is substituted . in an alternative preferred embodiment of the invention said modification comprises modification of amino acid residues 125 - 131 of the amino acid sequence in fig1 a ( seq id no : 1 ). preferably said modification is the deletion of all or part of amino acid residues 125 - 131 . in a preferred embodiment of the invention said fusion protein is an agonist . preferably said fusion protein comprises the amino acid sequence represented in fig2 ( seq id no : 3 ). in an alternative preferred embodiment of the invention said fusion protein is an antagonist . in a preferred embodiment of the invention said fusion protein comprises at least one site 2 modification to growth hormone . in a further preferred embodiment of the invention said fusion protein comprises at least one site 1 modification to growth hormone . in an alternative preferred embodiment of the invention said fusion protein comprises a site 2 and site 1 modification . in a preferred embodiment of the invention said fusion protein comprises growth hormone modified at amino acid residue glycine 120 of the amino acid sequence represented in fig2 ( seq id no : 3 ). preferably , the modification is substitution of glycine 120 with arginine ; alanine ; lysine ; tryptophan ; tyrosine ; phenylalanine ; or glutamic acid . in a preferred embodiment of the invention said modification is substitution of glycine 120 for arginine or lysine or alanine in a preferred embodiment of the invention said modification is substitution of glycine 120 for arginine . preferably said fusion protein comprises the amino acid sequence modifications : histidine 18 with aspartic acid , histidine 21 with asparagine , glycine 120 with arginine , arginine 167 with asparagine , lysine 168 with alanine , aspartic acid 171 with serine , lysine 172 with arginine , glutamic acid 174 with serine and isoleucine 179 with threonine . in a preferred embodiment of the invention said growth hormone or modified growth hormone is linked to said receptor polypeptide by a peptide linker ; preferably a flexible peptide linker . in a preferred embodiment of the invention said peptide linking molecule comprises at least one copy of the peptide gly gly gly gly ser ( seq id no : 35 ). in a preferred embodiment of the invention said peptide linking molecule comprises 2 , 3 , 4 , 5 , 6 or 7 copies of the peptide gly gly gly gly ser ( seq id no : 35 ). in an alternative preferred embodiment of the invention said peptide linker is modified to include at least one motif for the addition of at least one sugar moiety ; preferably said motif comprises asn - xaa - ser or asn - xaa - thr . in a preferred embodiment of the invention said peptide linker molecule comprises at least one copy of the motif ( xaa1 xaa2 xaa 3 xaa4 xaa 5 ) wherein said motif comprises the glycosylation motif asn - xaa - ser or asn - xaa - thr ( seq id no : 36 ). in a preferred embodiment of the invention said peptide linker comprises at least one copy of an amino acid motif selected from the group consisting of : asn 1 - xaa 2 - ser 3 xaa 4 xaa 5 wherein xaa 2 is any amino acid except proline ( seq id no : 37 ); xaa 1 asn 2 - xaa 3 - ser 4 xaa 5 wherein xaa 3 is any amino acid except proline ( seq id no : 38 ); xaa 1 xaa 2 asn 3 - xaa 4 - ser 5 wherein xaa 4 is any amino acid except proline ( seq id no : 39 ); asn 1 - xaa 2 - thr 3 xaa 4 xaa 5 wherein xaa 2 is any amino acid except proline ( seq id no : 40 ); xaa 1 asn 2 - xaa 3 - thr 4 xaa 5 wherein xaa 3 is any amino acid except proline ( seq id no : 41 ); and xaa 1 xaa 2 asn 3 - xaa 4 - thr 5 wherein xaa 4 is any amino acid except proline ( seq id no : 42 ). preferably said peptide linker comprises at least one copy of a motif selected from the group consisting of : asn 1 - xaa 2 - ser 3 gly 4 ser 5 wherein xaa 2 is any amino acid except proline ( seq id no : 43 ); gly 1 asn 2 - xaa 3 - ser4 ser 5 wherein xaa 3 is any amino acid except proline ( seq id no : 44 ); gly 1 gly 2 asn 3 - xaa 4 - ser 5 wherein xaa 4 is any amino acid except proline ( seq id no : 45 ); asn 1 - xaa 2 - thr 3 gly 4 ser 5 wherein xaa 2 is any amino acid except proline ( seq id no : 46 ); gly 1 asn 2 - xaa 3 - thr 4 ser 5 wherein xaa 3 is any amino acid except proline ( seq id no : 47 ); and glp gly 2 asn 3 - xaa 4 - thr 5 wherein xaa 4 is any amino acid except proline ( seq id no : 48 ). in an alternative preferred embodiment of the invention said peptide linker comprises at least one copy of a motif selected from the group consisting of : asn 1 - xaa 2 - ser 3 ser 4 gly 5 wherein xaa 2 is any amino acid except proline ( seq id no : 49 ); ser 1 asn 2 - xaa 3 - ser 4 gly 5 wherein xaa 3 is any amino acid except proline ( seq id no : 50 ); ser 1 ser 2 asn 3 - xaa 4 - ser 5 wherein xaa 4 is any amino acid except proline ( seq id no : 51 ); asn 1 - xaa 2 - thr 3 ser 4 gly 5 wherein xaa 2 is any amino acid except proline ( seq id no : 52 ); ser 1 asn 2 - xaa 3 - thr 4 gly 5 wherein xaa 3 is any amino acid except proline ( seq id no : 53 ); and ser 1 ser 2 asn 3 - xaa 4 - thr 5 wherein xaa a is any amino acid except proline ( seq id no : 54 ). in a preferred embodiment of the invention said peptide linker molecule comprises at least one copy of the motif ( xaa 1 xaa 2 xaa 3 xaa 4 xaa 5 ) wherein said motif comprises the glycosylation motif asn - xaa - ser or asn - xaa - thr and at least one copy of the motif ( gly gly gly gly ser ) ( seq id no : 35 ) wherein said peptide linker is 5 - 50 amino acids . in a preferred embodiment of the invention said peptide linker comprises at least one copy of the motif ( xaa 1 xaa 2 xaa 3 xaa 4 xaa 5 ) wherein said motif comprises the glycosylation motif asn - xaa - ser or asn - xaa - thr and a copy of the motif ( ser ser ser ser gly ) ( seq id no : 55 ) wherein said peptide linker is 5 - 50 amino acids . in a preferred embodiment of the invention said fusion polypeptide linker is modified by the addition of at least one sugar selected from the group consisting of : mannose , galactose , n - acetyl glucosamine , n - acetyl neuraminic acid , n - glycolyl neuraminic acid , n - acetyl galactosamine , fucose , glucose , rhamnose , xylose , or combinations of sugars , for example in an oligosacharide or scaffolded system . suitable carbohydrate moieties include monosaccharides , oligosaccharides and polysaccharides , and include any carbohydrate moiety that is present in naturally occurring glycoproteins or in biological systems . for example , optionally protected glycosyl or glycoside derivatives , for example optionally - protected glucosyl , glucoside , galactosyl or galactoside derivatives . glycosyl and glycoside groups include both α and β groups . suitable carbohydrate moieties include glucose , galactose , fucose , glcnac , galnac , sialic acid , and mannose , and oligosaccharides or polysaccharides comprising at least one glucose , galactose , fucose , glcnac , galnac , sialic acid , and / or mannose residue . any functional groups in the carbohydrate moiety may optionally be protected using protecting groups known in the art ( see for example greene et al , “ protecting groups in organic synthesis ”, 2nd edition , wiley , new york , 1991 , the disclosure of which is hereby incorporated by reference ). suitable protecting groups for any — oh groups in the carbohydrate moiety include acetate ( ac ), benzyl ( bn ), silyl ( for example tert - butyl dimethylsilyl ( tbdmsi ) and tert - butyldiphenylsilyl ( tmdpsi )), acetals , ketals , and methoxymethyl ( mom ). any protecting groups may be removed before or after attachment of the carbohydrate moiety to the peptide linker . in a preferred embodiment of the invention said sugars are unprotected . particularly preferred carbohydrate moieties include glc ( ac ) 4 β -, glc ( bn ) 4 β -, gal ( ac ) 4 β -, gal ( bn ) 4 β -, glc ( ac ) 4 α ( 1 , 4 ) glc ( ac ) 3 α ( 1 , 4 ) glc ( ac ) 4 β -, β - glc , β - gal , - et - β - gal , - et - β - glc , et - α - glc , - et - α - man , - et - lac , - β - glc ( ac ) 2 , - β - glc ( ac ) 3 , - et - α - glc ( ac ) 2 , - et - α - glc ( ac ) 3 , - et - α - glc ( ac ) 4 , - et - β - glc ( ac ) 2 , - et - β - glc ( ac ) 3 , - et - β - glc ( ac ) 4 , - et - α - man ( ac ) 3 , - et - α - man ( ac ) 4 , - et - β - gal ( ac ) 3 , - et - β - gal ( ac ) 4 , - et - lac ( ac ) 5 , - et - lac ( ac ) 6 , - et - lac ( ac ) 7 , and their deprotected equivalents . preferably , any saccharide units making up the carbohydrate moiety which are derived from naturally occurring sugars will each be in the naturally occurring enantiomeric form , which may be either the d - form ( e . g . d - glucose or d - galactose ), or the l - form ( e . g . l - rhamnose or l - fucose ). any anomeric linkages may be α - or β - linkages . in a still further alternative embodiment of the invention said fusion protein does not comprise a peptide linking molecule and is a direct fusion of growth hormone or modified growth hormone and the receptor polypeptide according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig3 ( seq id no : 4 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig4 ( seq id no : 5 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig5 ( seq id no : 6 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 321 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig6 ( seq id no : 7 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig7 ( seq id no : 8 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig8 ( seq id no : 9 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 321 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig9 ( seq id no : 10 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 11 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 12 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 321 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 13 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 14 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 15 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 16 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 17 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 18 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 19 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 349 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig1 ( seq id no : 20 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 21 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 22 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 23 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 24 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 25 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 26 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 27 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 28 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 346 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 29 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 349 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig2 ( seq id no : 30 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 349 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig3 ( seq id no : 31 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 349 . according to a further aspect of the invention there is provided a fusion protein comprising the amino acid sequence as represented in fig3 ( seq id no : 32 ) wherein said amino acid sequence is modified by substitution at amino acid residue tryptophan 349 . in a preferred embodiment of the invention tryptophan is substituted for alanine . according to an aspect of the invention there is provided a nucleic acid molecule that encodes a fusion polypeptide according to the invention or a nucleic acid molecule that hybridizes to said nucleic acid molecule and encodes a polypeptide wherein said polypeptide has growth hormone receptor agonist or antagonist activity . hybridization of a nucleic acid molecule occurs when two complementary nucleic acid molecules undergo an amount of hydrogen bonding to each other . the stringency of hybridization can vary according to the environmental conditions surrounding the nucleic acids , the nature of the hybridization method , and the composition and length of the nucleic acid molecules used . calculations regarding hybridization conditions required for attaining particular degrees of stringency are discussed in sambrook et al ., molecular cloning : a laboratory manual ( cold spring harbor laboratory press , cold spring harbor , n . y ., 2001 ); and tijssen , laboratory techniques in biochemistry and molecular biology — hybridization with nucleic acid probes part i , chapter 2 ( elsevier , new york , 1993 ). the t m is the temperature at which 50 % of a given strand of a nucleic acid molecule is hybridized to its complementary strand . the following is an exemplary set of hybridization conditions and is not limiting : very high stringency ( allows sequences that share at least 90 % identity to hybridize ) hybridization : 5 × ssc at 65 ° c . for 16 hours wash twice : 2 × ssc at room temperature ( rt ) for 15 minutes each wash twice : 0 . 5 × ssc at 65 ° c . for 20 minutes each high stringency ( allows sequences that share at least 80 % identity to hybridize ) hybridization : 5 ×- 6 × ssc at 65 ° c .- 70 ° c . for 16 - 20 hours wash twice : 2 × ssc at rt for 5 - 20 minutes each wash twice : 1 × ssc at 55 ° c .- 70 ° c . for 30 minutes each low stringency ( allows sequences that share at least 50 % identity to hybridize ) hybridization : 6 × ssc at rt to 55 ° c . for 16 - 20 hours wash at least twice : 2 ×- 3 × ssc at rt to 55 ° c . for 20 - 30 minutes each . according to a further aspect of the invention there is provided a vector comprising a nucleic acid molecule according to the invention . in a preferred embodiment of the invention said vector is an expression vector adapted to express the nucleic acid molecule according to the invention . a vector including nucleic acid ( s ) according to the invention need not include a promoter or other regulatory sequence , particularly if the vector is to be used to introduce the nucleic acid into cells for recombination into the genome for stable transfection . preferably the nucleic acid in the vector is operably linked to an appropriate promoter or other regulatory elements for transcription in a host cell . the vector may be a bi - functional expression vector which functions in multiple hosts . by “ promoter ” is meant a nucleotide sequence upstream from the transcriptional initiation site and which contains all the regulatory regions required for transcription . suitable promoters include constitutive , tissue - specific , inducible , developmental or other promoters for expression in eukaryotic or prokaryotic cells . “ operably linked ” means joined as part of the same nucleic acid molecule , suitably positioned and oriented for transcription to be initiated from the promoter . dna operably linked to a promoter is “ under transcriptional initiation regulation ” of the promoter . in a preferred embodiment the promoter is a constitutive , an inducible or regulatable promoter . according to a further aspect of the invention there is provided a cell transfected or transformed with a nucleic acid molecule or vector according to the invention . in a preferred embodiment of the invention said cell is selected from the group consisting of ; a fungal cell ( e . g . pichia spp , saccharomyces spp , neurospora spp ); insect cell ( e . g . spodoptera spp ); a mammalian cell ( e . g . cos cell , cho cell ); a plant cell . in a preferred embodiment of the invention said cell is stably transfected . in an alternative preferred embodiment of the invention said cell is transiently transfected . according to a further aspect of the invention there is provided a pharmaceutical composition comprising a polypeptide according to the invention including an excipient or carrier . in a preferred embodiment of the invention said pharmaceutical composition is combined with a further therapeutic agent . when administered the pharmaceutical composition of the present invention is administered in pharmaceutically acceptable preparations . such preparations may routinely contain pharmaceutically acceptable concentrations of salt , buffering agents , preservatives , compatible carriers , and optionally other therapeutic agents for example chemotherapeutic agents . the pharmaceutical compositions of the invention can be administered by any conventional route , including injection . the administration and application may , for example , be oral , intravenous , intraperitoneal , intramuscular , intracavity , intra - articuar , subcutaneous , topical ( eyes ), dermal ( e . g a cream lipid soluble insert into skin or mucus membrane ), transdermal , or intranasal . pharmaceutical compositions of the invention are administered in effective amounts . an “ effective amount ” is that amount of pharmaceuticals / compositions that alone , or together with further doses or synergistic drugs , produces the desired response . this may involve only slowing the progression of the disease temporarily , although more preferably , it involves halting the progression of the disease permanently . this can be monitored by routine methods or can be monitored according to diagnostic methods . the doses of the pharmaceuticals compositions administered to a subject can be chosen in accordance with different parameters , in particular in accordance with the mode of administration used and the state of the subject ( i . e . age , sex ). when administered , the pharmaceutical compositions of the invention are applied in pharmaceutically - acceptable amounts and in pharmaceutically - acceptable compositions . when used in medicine salts should be pharmaceutically acceptable , but non - pharmaceutically acceptable salts may conveniently be used to prepare pharmaceutically - acceptable salts thereof and are not excluded from the scope of the invention . such pharmacologically and pharmaceutically - acceptable salts include , but are not limited to , those prepared from the following acids : hydrochloric , hydrobromic , sulfuric , nitric , phosphoric , maleic , acetic , salicylic , citric , formic , malonic , succinic , and the like . also , pharmaceutically - acceptable salts can be prepared as alkaline metal or alkaline earth salts , such as sodium , potassium or calcium salts . the pharmaceutical compositions may be combined , if desired , with a pharmaceutically - acceptable carrier . the term “ pharmaceutically - acceptable carrier ” as used herein means one or more compatible solid or liquid fillers , diluents or encapsulating substances that are suitable for administration into a human . the term “ carrier ” denotes an organic or inorganic ingredient , natural or synthetic , with which the active ingredient is combined to facilitate the application . the components of the pharmaceutical compositions also are capable of being co - mingled with the molecules of the present invention , and with each other , in a manner such that there is no interaction that would substantially impair the desired pharmaceutical efficacy . the pharmaceutical compositions may contain suitable buffering agents , including : acetic acid in a salt ; citric acid in a salt ; boric acid in a salt ; and phosphoric acid in a salt . the pharmaceutical compositions also may contain , optionally , suitable preservatives , such as : benzalkonium chloride ; chlorobutanol ; parabens and thimerosal . the pharmaceutical compositions may conveniently be presented in unit dosage form and may be prepared by any of the methods well - known in the art of pharmacy . all methods include the step of bringing the active agent into association with a carrier that constitutes one or more accessory ingredients . in general , the compositions are prepared by uniformly and intimately bringing the active compound into association with a liquid carrier , a finely divided solid carrier , or both , and then , if necessary , shaping the product . compositions suitable for oral administration may be presented as discrete units , such as capsules , tablets , lozenges , each containing a predetermined amount of the active compound . other compositions include suspensions in aqueous liquids or non - aqueous liquids such as syrup , elixir or an emulsion . compositions suitable for parenteral administration conveniently comprise a sterile aqueous or non - aqueous preparation that is preferably isotonic with the blood of the recipient . this preparation may be formulated according to known methods using suitable dispersing or wetting agents and suspending agents . the sterile injectable preparation also may be a sterile injectable solution or suspension in a non - toxic parenterally - acceptable diluent or solvent , for example , as a solution in 1 , 3 - butane diol . among the acceptable solvents that may be employed are water , ringer &# 39 ; s solution , and isotonic sodium chloride solution . in addition , sterile , fixed oils are conventionally employed as a solvent or suspending medium . for this purpose any bland fixed oil may be employed including synthetic mono - or di - glycerides . in addition , fatty acids such as oleic acid may be used in the preparation of injectables . carrier formulation suitable for oral , subcutaneous , intravenous , intramuscular , etc . administrations can be found in remington &# 39 ; s pharmaceutical sciences , mack publishing co ., easton , pa . according to a further aspect of the invention there is provided a method to treat a human subject suffering from growth hormone deficiency comprising administering an effective amount of at least one polypeptide according to the invention . in a preferred method of the invention said growth hormone deficiency is childhood growth hormone deficiency . in a preferred method of the invention said growth hormone deficiency is adult growth hormone deficiency . the treatment of growth hormone deficiency includes for example the treatment of turners syndrome , prader willi syndrome , interuterine growth retardation , idiopathic short stature , renal failure , catabolic states for example during chemotherapy treatment and in the treatment of aids . according to a further aspect of the invention there is provided a method to treat a human subject suffering from growth hormone excess comprising administering an effective amount of at least one polypeptide according to the invention . in a preferred method of the invention said growth hormone excess results in gigantism . in a preferred method of the invention said growth hormone excess results in acromegaly . according to a further aspect of the invention there is provided a method to treat a human subject suffering from cancer comprising administering an effective amount of at least one polypeptide according to the invention . as used herein , the term “ cancer ” refers to cells having the capacity for autonomous growth , i . e ., an abnormal state or condition characterized by rapidly proliferating cell growth . the term is meant to include all types of cancerous growths or oncogenic processes , metastatic tissues or malignantly transformed cells , tissues , or organs , irrespective of histopathologic type or stage of invasiveness . the term “ cancer ” includes malignancies of the various organ systems , such as those affecting , for example , lung , breast , thyroid , lymphoid , gastrointestinal , and genito - urinary tract , as well as adenocarcinomas which include malignancies such as most colon cancers , renal - cell carcinoma , prostate cancer and / or testicular tumours , non - small cell carcinoma of the lung , cancer of the small intestine and cancer of the esophagus . the term “ carcinoma ” is art recognized and refers to malignancies of epithelial or endocrine tissues including respiratory system carcinomas , gastrointestinal system carcinomas , genitourinary system carcinomas , testicular carcinomas , breast carcinomas , prostatic carcinomas , endocrine system carcinomas , and melanomas . exemplary carcinomas include those forming from tissue of the cervix , lung , prostate , breast , head and neck , colon and ovary . the term “ carcinoma ” also includes carcinosarcomas , e . g ., which include malignant tumours composed of carcinomatous and sarcomatous tissues . an “ adenocarcinoma ” refers to a carcinoma derived from glandular tissue or in which the tumor cells form recognizable glandular structures . the term “ sarcoma ” is art recognized and refers to malignant tumors of mesenchymal derivation . in a preferred method of the invention said cancer is prostate cancer . in a preferred method of the invention said polypeptide is administered intravenously . in an alternative preferred method of the invention said polypeptide is administered subcutaneously . in a further preferred method of the invention said polypeptide is administered daily or at two day intervals ; preferably said polypeptide is administered at weekly , 2 weekly or monthly intervals . throughout the description and claims of this specification , the words “ comprise ” and “ contain ” and variations of the words , for example “ comprising ” and “ comprises ”, means “ including but not limited to ”, and is not intended to ( and does not ) exclude other moieties , additives , components , integers or steps . throughout the description and claims of this specification , the singular encompasses the plural unless the context otherwise requires . in particular , where the indefinite article is used , the specification is to be understood as contemplating plurality as well as singularity , unless the context requires otherwise . features , integers , characteristics , compounds , chemical moieties or groups described in conjunction with a particular aspect , embodiment or example of the invention are to be understood to be applicable to any other aspect , embodiment or example described herein unless incompatible therewith . an embodiment of the invention will now be described by example only and with reference to the following figures : fig1 a is the amino acid sequence of human growth hormone receptor extracellular domain ( seq id no : 1 ); the amino acid sequence of human growth hormone receptor extracellular domain without the signal sequence indicated in the figure is set forth as seq id no : 69 . fig1 b ( seq id no : 2 ) is the amino acid sequence of human growth hormone receptor extracellular domain with a tryptophan 104 to alanine substitution ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 3 ) is the amino acid sequence of human growth hormone ; signal sequence is shown in bold and is optional the amino acid sequence of human growth hormone without the signal sequence indicated in the figure is set forth as seq id no : 70 ; fig3 ( seq id no : 4 ) is the amino acid sequence of growth hormone fusion protein 1b7 - v1 ; signal sequence is shown in bold and is optional . the corresponding amino acid sequence without the signal sequence is set forth herein as seq id no : 71 ; fig4 ( seq id no : 5 ) is the amino acid sequence of growth hormone fusion protein 1b7 - v2 ; signal sequence is shown in bold and is optional . the corresponding amino acid sequence without the signal sequence is set forth herein as seq id no : 72 ; fig5 ( seq id no : 6 ) is the amino acid sequence of growth hormone fusion protein 1b7 - v3 ; signal sequence is shown in bold and is optional . the corresponding amino acid sequence without the signal sequence is set forth herein as seq id no : 73 ; fig6 ( seq id no : 7 ) is the amino acid sequence of growth hormone fusion protein 1b8 - v1 ; signal sequence is shown in bold and is optional ; fig7 ( seq id no : 8 ) is the amino acid sequence of growth hormone fusion protein 1b8 - v2 ; signal sequence is shown in bold and is optional ; fig8 ( seq id no : 9 ) is the amino acid sequence of growth hormone fusion protein 1b8 - v3 ; signal sequence is shown in bold and is optional ; fig9 ( seq id no : 10 ) is the amino acid sequence of growth hormone fusion protein 1b9 - v1 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 11 ) is the amino acid sequence of growth hormone fusion protein 1b9 - v2 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 12 ) is the amino acid sequence of growth hormone fusion protein 1b9 - v3 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 13 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g1 - v1 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 14 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g1 - v2 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 15 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g2 - v1 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 16 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g2 - v2 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 17 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g3 - v1 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 18 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g3 - v2 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 19 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g4 - v1 ; signal sequence is shown in bold and is optional ; fig1 ( seq id no : 20 ) is the amino acid sequence of growth hormone fusion protein 1b7 - g4 - v2 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 21 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g1 - v1 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 22 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g1 - v2 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 23 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g1 - v1 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 24 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g1 - v2 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 25 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g3 - v1 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 26 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g3 - v2 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 27 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g3 - v1 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 28 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g3 - v2 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 29 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g4 - v1 ; signal sequence is shown in bold and is optional ; fig2 ( seq id no : 30 ) is the amino acid sequence of growth hormone fusion protein 1b8 - g4 - v2 ; signal sequence is shown in bold and is optional ; fig3 ( seq id no : 31 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g4 - v1 ; signal sequence is shown in bold and is optional ; and fig3 ( seq id no : 32 ) is the amino acid sequence of growth hormone fusion protein 1b9 - g4 - v2 ; signal sequence is shown in bold and is optional . fig3 western blot of native page gel showing the separation of 1b7v2 wildtype , ( lane 1 ) and 1b7v2 w104 mutant ( lane 2 ). the image shows that the inclusion of the mutation , w104a in the ghr moiety in 1b7v2_w104 prevents formation of what is thought to be a dimer between 1b7v2 molecules : formation of this dimer is thought to be primarily the results of intermolecular association of gh with ghr ; fig3 : western blot of sds - page gel showing separation of 1b7v2_w104a ; transfection 1 ( lane 1 ), 1b7v2_w104a ; transfection 2 , ( lane 2 ) and 1b7v2_wild type ( lane 3 ). both molecules are detected at around 75 kda ; fig3 : corrected luciferase data from a dual luciferase bioassay performed in 293 hi cells shows increased bioactivity for 1b7v2_hist_w104 mutant compared to the non - mutant 1b7v2_hist . this shows that inclusion of the mutant may indeed increase bioactivity of the 1b7v2 molecule ; fig3 plate 1 : rhgh standard curve ; plate 2 : media from stable ghwt transfected cells ; plate 3 : media from stable 1b7v2_wt transfected cells ; plate 4 : media from stable 1b7v2_w104a transfected cells ; plate 5 : control media samples ; and fig3 illustrates the stimulation of proliferation of nb2 cells by 1b7v2_w104a mutant compared to recombinant human growth hormone and 1b7v2_wt . the nucleic and / or amino acid sequences provided herewith are shown using standard letter abbreviations for nucleotide bases , and three letter code for amino acids , as defined in 37 c . f . r . 1 . 822 . only one strand of each nucleic acid sequence is shown , but the complementary strand is understood as included by any reference to the displayed strand . the sequence listing is submitted as an ascii text file named 96064_301_1001 seq . txt , created oct . 2 , 2016 , about 164 kb , which is incorporated by reference herein . all the materials were purchased from sigma ( poole , uk ) unless otherwise stated . recombinant gh was purchased from pfizer , recombinant e . coli derived human gh binding protein used in binding assays was a gift from dsl ( dsl research reagents , oxfordshire , uk ), and iodinated gh a gift from novonordisk ( novonordisk park , denmark ). gh and ghr mabs used for purification and characterisation were in - house materials . construction expression and testing of 1b7v2 / v3 molecules containing a tryptophan - 104 ( w104 ) to alanine ( a104 ) substitution 1 . digest pghsectag - 1b7v0 - hist using the restriction enzymes ecorv and agei ( see fig2 . 1 ( seq id no : 56 ) sequence ). this molecule contains a histidine tag at the c - terminal and therefore does not have a stop codon in this region ( see fig2 . 2 ( seq id no : 57 ) for sequence ) 2 . take pghsectag - 1b7v2 and v3 molecules ( these molecules contain a stop codon prior to the hist tag and therefore are not hist tagged , see fig1 . 4 ). replacing the ecorv / agei sequence in this molecule with the sequence from pghsectag - 1b7v0 - hist ( fig2 . 2 ( seq id no : 57 )) will allow read through to the hist - tag . ecorv and agei sites shown in red . hist tag shown in italics and underlined . linker in bold . signal sequence underlined the ecorv and agei sites are shown in red . linker in bold . hist tag underlined and in italics . stop codon in large font note : same reaction is performed for the construction of 1b7v3_hist molecule use as template pghsectag - 1b7v2 hist . after construction of the w104 mutation , the mutation can simply be transferred to other constructs ( 1b7v2 and ghbp_hist ) using avrii / hindiii enzymes . aim : the highlighted dna ( see sequence below ) will be multiplied by pcr ( polymerase chain reaction ) using dna primers that include both avrii , ecori and w104 mutations . the method produces 2 pcr fragements , both including the w104 mutation . using overlapping pcr ( i . e . both dna fragments will anneal to each other due to overlapping sequences ) we will produce a full length dna insert with flanking avrii and ecori sites . this can then be digested with both enzymes and ligated into the appropriate vector . sequence showing ghr portion of 1b7 molecule : w104a mutation is underlined . avrii and ecorv site are shown in orange ( seq id no : 60 ) primer 1 = ghr - avrii : forward primer : binds 5 ′ end of ghr and includes the endogenous restriction site avrii ( c & gt ; ctagg ). the avrii site is shown underlined , ghr sequence is in italics ( 5 ′& gt ; 3 ′). tm = 60 c . 28mer primer 2 = ghr_w104rev : reverse primer contains the w104 mutation ( w & gt ; a , tgg & gt ; gca ). also contains overlapping sequence to pcr reaction 2 . primer 3 = ghr_ecorvrev . reverse primer binds to the 3 ′ end of ghr and includes the endogenous restriction site ecorv . the ecorv site is shown in square brackets . the ghr sequence is shown in italics . tm = 62 c using expand enzyme system . gel isolate pcr fragments on 1 % agarose / tae gel using qiagen gel isolation kit . nb : add template last to the reaction mix . add water and dntp first to prevent contamination by template . do not take out mm2 material until mmi has been prepared to avoid cross contamination . place mmi on ice until ready . positive control ; sample known to produce product under pcr conditions : gh template ( ghstop template with gh1 - 23 and gh hindrev primers ). negative controls are above reaction but no template . mix 25 ul of mmi with 25 ul mmii and overlay with mineral oil . 95 c for 2 min , [ 95 c for 30 sec ; 54 c for 30 sec ; 72 c for 30 sec ] 25 cycles , 72 c for 10 min the above pcr reaction is repeated for pcr2 ( replace with appropriate primers ) overlapping pcr reaction . pcr fragments from reactions 1 and 2 are annealed and pcr amplified using appropriate forward and reverse primers that include the restriction enztme sites avrii and ecori . nb : add template last to the reaction mix . add water and dntp first to prevent contamination by template . do not take out mm2 material until mmi has been prepared to avoid cross contamination . gel isolate pcr fragment on 1 % agarose / tae gel using qiagen gel isolation kit . restriction digest reaction will be set up as follows : 24 hours at 37 c . isolate digested fragment and analyse digests by tae / agarose . estimate concentration by agarose gel running against standards or use nanodrop 260 nm . set up an initial ratio of plasmid to insert of 1 : 3 ( molar ) in a total volume of 10 - 15 ul calculate amount of fragment to use as follows ( taken from promega t4 dna ligase data sheet ) leave @ 37 c for 3 hours or o / n . also set up reaction without ligase . took 5 ul of above ligation and added to xl1 - blue chemically competent cells . leave for 30 minutes on ice , then heat shock @ 42 c . leave on ice for a further 30 minutes . plate out ligation mix onto freshly prepared agar plates containing 100 ug / ml carbenicillin . leave o / n 37 c . prepare plasmid from + ve clones and check authenticity by restriction digestion using nhe1 / hindiii ( produces full length clone ). these ligations produce the following constructs : pick isolated single colony and streak into an agar grid plate , and then add remainder to 5 ul sdw as template . 95 c for 2 min , [ 95 c for 30 sec ; 52 c for 30 sec ; 72 c for 30 sec ] 35 cycles , 72 c for 10 min submit at least 2 clones for sequencing : send each plasmid in at least 10 ul @ 100 ng / ul ( 1 ug total ) along with relevant primers @ 1 pmol / ul ( send at least 10 ul ) 1 . use trypsin - edta to remove cho cells from a flask and resuspend in dmem + 10 % fcs , 4 mm l - glutamine . 2 . seed @ 2 × 10e5 cho cells into wells of a 24 well - plate , using 1 ml per well . remember to leave room for a non - transfected control . leave o / n to attach . 3 . the following day transfect using fugene - 6 ( or mirus ) at a ratio of 3 : 2 to dna i . e . add 4 microg dna to 6 ul fugene - 6 in a volume of 100 ul serum free media . briefly , warm fugene - 6 to rmt and premix by vortexing . pippette 6 ul into 100 ul serum free media . gently mix by flicking , add dna , and again mix by flicking gently . leave at rmt for 15 minutes . pippette transfection mix into individual wells , swirl well contents to ensure even distribution . do not allow fugene - 6 to come into contact with the plastic sides of the tubes being used . 4 . leave cells for 24 hrs and change media if required to serum free . leave cells 48 - 72 hrs post treatment before harvesting media . 5 . product titre normally levels off after about 3 - 5 days . 6 . test expression using both native and sds - page a mammalian expression system has been established using a modified invitrogen vector psectag - v5 / frt - hist . this vector is used in invitrogen &# 39 ; s flp - in system to direct integration of the target gene into the host cell line , allowing rapid generation of stable clones into specific sites within the host genome for high expression . culturing flp - in cell lines ; followed manufactures instruction using basic cell culture techniques . stable cell lines were generated in 6 - well plates using fugene - 6 as the transfection reagent . the cho flp - in cells were co - transfected with the expression vector and pog44 , a plasmid that expresses flp recombinase an enzyme which causes the recombination of the lr - fusion gene into a “ hot - spot ” of the cell chromosome . hygromycin b was used to select for cells with positive recombinants . human gh and gh receptor were amplified by rt - pcr from human pituitary and liver respectively and cloned into the vector , psectag - v5 / frt / hist - topo ( invitrogen , paisley , uk ) under the human gh secretion signal sequence . four repeats of a gly 4 ser linker were used to link the native c - terminus of human gh to the native n - terminus of the human ghr . stable clones were made in cho flp - in cells ( invitrogen , paisley , uk ), adapted to protein free media and grown in suspension culture . lr - fusion expression was confirmed by an in - house elisa . affinity purification was performed using a gh mab column . these were performed as previously described in human 293 cells stably expressing the human ghr 16 . elisa . an in house gh and fusion elisa has been established based on the sandwich elisa format . in the assay , standards ( gh or fusion ), controls and unknowns are incubated with biotin - labelled mouse antibody to human gh ( mab 7f8 ) in wells pre - coated with a mouse antibody to human gh antibody ( mab 10a7 ). the detection limit for the assay is 2 . 5 pg and the intra and inter assay cv is & lt ; 10 %. the igf - i elisa was purchased from dsl ( dsl - 10 - 2900 active mouse / rat igf - i kit ; dsl research reagents , oxfordshire , uk ). the ability of the cell line nb2 to proliferate in the presence of lactogen and assaying of endogenous dehydrogenase activity using the celltitre assay reagent ( promega ) non - radioactive proliferation assay reagents ( cat # g358c , lot # 24464403 , ready to use one solution reagent : add 20 ul directly to media ) 1 . take nb2 cells and wash twice with ˜ 20 ml of assay media . resuspend at 5 . 5 × 10e5 cells per ml in assay media . 2 . grow cells o / n in t75 flasks to deplete the cells of lactogen @ 37 c , 5 % co2 . 3 . for the assay : count cells and adjust density to ˜ 2 × 10e4 cells in 50 ul ( 4 × 10e5 cells per ml ) in assay media . plate on a 96 well plate ( require 100 × 50 ×( 2 × 10e4 )= 2 × 10e6 cells ) 4 . prepare a series of prl standards as show in table below . prepare sample and control dilutions as shown . add 50 ul of each to allocated wells . 5 . grow cells in the presence of standards and test samples for ˜ 3 days @ 37c / 5 % co2 . 6 . to assay : add 20 ul of celltitre reagent ( promega celltitre 96 aqueous ) and leave at 37 c for 2 - 6 hrs 7 . record the a490 nm reading of each well using a microplate reader . seven week old normal sprague dawley rats from janvier ( le genest saint isle , france ) were used for pharmacokinetic studies . sc or iv administration ( penile vein ) and blood withdrawal ( orbital sinus ) were conducted under isoflurane anaesthesia . the rats ( n = 4 - 6 / group ) were injected iv or sc with of 0 . 1 mg / kg rhgh or fusion . blood samples were collected from the retro - orbital plexus . serum was harvested and stored at − 70 ° c . until assays . pharmacokinetic parameters were estimated by fitting values of hormone concentration versus time to compartmental models using non - linear least - squares regression analysis . clearance values were normalized to animal weight . clearance rate per animal weight and terminal half lives ( t 1 / 2 ) were calculated using the coefficient and exponents obtained from the iv bolus model fits . the test substances were formulated in solutions containing 11 . 9 mm sodium and potassium phosphates , 137 mm sodium chloride , 2 . 7 mm potassium chloride , 0 . 01 % polysorbate 80 ; ph of the solution was adjusted to 7 . 4 . blood samples were obtained from all animals throughout the study in order to determine the concentration of the appropriate test material in serum . these samples were taken at a number of time points throughout the study . the serum concentration of ib7v2 and ib7v3 was determined using a validated elisa method . the pharmacokinetic profile for each of the protein was determined by plotting the concentration for each of the protein in serum versus time using winnonlin pro ( v4 . 0 . 1 ) software . the growth studies used hypophysectomized rats and were performed on sprague dawley rats from charles river laboratories ( larbresle , france ). rats were hypophysectomized under isoflurane anaesthesia at 4 weeks of age by the breeder and delivered one week after selection on body weight criteria for successful surgery . animals were individually caged and allowed another week of rest before entering the experimental phase . the injection solutions of excipient , rhgh and fusion never exceeded 2 ml / kg . the rats were weighed daily and depending on the administration protocol , received injections of the test substances for 10 days . conformation of the fusion protein was examined using a panel of 16 conformationally sensitive hgh receptor mabs . denaturing , native gels and western blotting were used to analyse the lr - fusion and western blotting performed with non - conformationally sensitive to gh . the form of the lr - fusion protein in solution was defined by gel filtration using a superose g200 analytical column and analytical ultracentrifugation . analytical ultracentrifugation ( auc ) was performed by sedimentation velocity ( analytical service , dr andy barry , astbury , leeds university , leeds , uk ). two groups were compared with a student &# 39 ; s test if their variance was normally distributed or by a student - satterthwaite &# 39 ; s test if not normally distributed . distribution was tested with an f test . one - way anova was used to compare the means of 3 or more groups and if the level of significance was p & lt ; 0 . 05 individual comparisons were performed with dunnett &# 39 ; s tests . all statistical tests were two - sided at the 5 % level of significance and no imputation was made for missing values . ghwt as expected shows comparable activity to rhgh ; 1b7v2_wt shows lower activity than rhgh at equivalent concentrations ( usually 10 - 20 fold less ). however , the mutant 1b7v2_w104a mutant shows increased activity at all concentrations studied . this may imply that the presence of the w104a mutation which prevents dimerisation of the 1b7v2 molecule , increases its activity by increasing the bioavailability of monomeric 1b7v2 . the nb2 cell line shows a greater level of proliferation in the presence of the 1b7v2_w104a mutant when compared to 1b7v2_wt . the growth curve for 1b7v2_w104a is shifted closer to rhgh . this may imply that the presence of the w104a mutation which prevents dimerisation of the 1b7v2 molecule , increases its activity by increasing the bioavailability of monomeric 1b7v2 . 1 . woodhouse , l . j ., mukherjee , a ., shalet , s . m . & amp ; ezzat , s . the influence of growth hormone status on physical impairments , functional limitations , and health - related quality of life in adults . endocr rev . 27 , 287317 ( 2006 ). 2 . clark , r . et al . long - acting growth hormones produced by conjugation with polyethylene glycol . journal of biological chemistry . 271 , 2196921977 ( 1996 ). 3 . cook , d . m . et al . the pharmacokinetic and pharmacodynamic characteristics of a long - acting growth hormone ( gh ) preparation ( nutropin depot ) in gh - deficient adults . j clin endocrinol metab . 87 , 450814 ( 2002 ). 4 . reiter , e . o . et al . a multicenter study of the efficacy and safety of sustained release gh in the treatment of naive pediatric patients with gh deficiency . 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[ review ] [ 58 refs ]. international archives of allergy & amp ; immunology . 111 , 99106 ( 1996 ). 9 . baumann , g ., amburn , k . d . & amp ; buchanan , t . a . the effect of circulating growth hormone - binding protein on metabolic clearance , distribution , and degradation of human growth hormone . j clin endocrinol metab . 64 , 65760 ( 1987 ). 10 . baumann , g . growth hormone heterogeneity : genes , isohormones , variants , and binding proteins . endocrine reviews 12 , 424449 ( 1991 ). 11 . baumann , g ., shaw , m . a . & amp ; buchanan , t . a . in vivo kinetics of a covalent growth hormone - binding protein complex . metabolism . 38 , 3303 ( 1989 ). 12 . clark , r . g . et al . recombinant human growth hormone ( gh )- binding protein enhances the growth - promoting activity of human gh in the rat . endocrinology . 137 , 43084315 ( 1996 ). 13 . baumann , g . growth hormone binding protein -- errant receptor or active player ? 14 . ayling , r . m . et al . a dominant - negative mutation of the growth hormone receptor causes familial short stature . nature genetics . 16 , 1314 ( 1997 ). 15 . ross , r . j . et al . a short isoform of the human growth hormone receptor functions as a dominant negative inhibitor of the full - length receptor and generates large amounts of binding protein . molecular endocrinology . 11 , 265273 ( 1997 ). 16 . ross , r . j . m . et al . binding and functional studies with the growth hormone receptor antagonist , b2036 - peg ( pegvisomant ), reveal effects of pegylation and evidence that it binds to a receptor dimer . journal of clinical endocrinology & amp ; metabolism . 86 , 17161723 ( 2001 ). 17 . cunningham , b . c . et al . dimerization of the extracellular domain of the human growth hormone receptor by a single hormone molecule . science . 254 , 821825 ( 1991 ). 18 . huston , j . s ., tai , m . s ., mccartney , j ., keck , p . & amp ; oppermann , h . antigen recognition and targeted delivery by the single - chain fv . cell biophys . 22 , 189 - 224 ( 1993 ). 19 . herington , a . c ., smith , a . i ., wallace , c . & amp ; stevenson , j . l . partial purification from human serum of a specific binding protein for human growth hormone . mol cell endocrinol . 53 , 2039 ( 1987 ). 20 . frick , g . p ., tai , l . r ., baumbach , w . r . & amp ; goodman , h . m . tissue distribution , turnover , and glycosylation of the long and short growth hormone receptor isoforms in rat tissues . endocrinology . 139 , 282430 ( 1998 ). 21 . mannor , d . a ., winer , l . m ., shaw , m . a . & amp ; baumann , g . plasma growth hormone ( gh )- binding proteins : effect on gh binding to receptors and gh action . j clin endocrinol metab . 73 , 304 ( 1991 ). 22 . lim , l ., spencer , s . a ., mckay , p . & amp ; waters , m . j . regulation of growth hormone ( gh ) bioactivity by a recombinant human gh - binding protein . endocrinology . 127 , 128791 ( 1990 ). 23 . haffner , d ., schaefer , f ., girard , j ., ritz , e . & amp ; mehls , o . metabolic clearance of recombinant human growth hormone in health and chronic renal failure . j clin invest . 93 , 116371 ( 1994 ). 24 . johnson , v . & amp ; maack , t . renal extraction , filtration , absorption , and catabolism of growth hormone . american journal of physiology 233 , f185f196 ( 1977 ). 25 . veldhuis , j . d . et al . impact of experimental blockade of peripheral growth hormone ( gh ) receptors on the kinetics of endogenous and exogenous gh removal in healthy women and men . journal of clinical endocrinology & amp ; metabolism 87 , 57375745 ( 2002 ). 26 . osborn , b . l . et al . albutropin : a growth hormone - albumin fusion with improved pharmacokinetics and pharmacodynamics in rats and monkeys . eur j pharmacol 456 , 14958 ( 2002 ). 27 . de vos , a . m ., ultsch , m . & amp ; kossiakoff , a . a . human growth hormone and extracellular domain of its receptor : crystal structure of the complex . science 255 , 306312 ( 1992 ).