bluuebunny/crossref_metadata_2025_split huggingface dataset:
An enzyme-linked immunoadsorbent assay for human pituitary glycoprotein free α-subunit: evaluation and initial experience in patients with pituitary disease
Authors: Anyaoku V. N. , Wood D. F. , Pavlou R. , Williams P. , Tan K. , Fidler S. , Johnston D. G. 
Published: December 2008

ABSTRACT
An enzyme-linked immunoadsorbent assay (ELISA) for measuring human pituitary glycoprotein free α-subunit is described. Pituitary tumours may secrete glycoprotein hormones, their free subunits (α, β) or a combination of these. Non-functioning adenomas often secrete free α-subunit. Assays for free α-subunit have previously used radioimmunoassay or immunoradiometric principles. Some of these methods are time-consuming and lack specificity and sensitivity. In order to overcome these problems, we have developed a two-site ELISA for α-subunit which uses a monoclonal antibody to α-subunit as the capture antibody to provide greater specificity. An affinity-purified polyclonal anti α-subunit conjugated to alkaline phosphatase was the signal antibody. Detection and quantification were based on phenolphthalein monophosphate conversion to phenolphthalein. The ELISA specifically measured glycoprotein free α-subunit in serum or plasma, discriminating between α-subunit and the intact glycoprotein hormones. The assay can be completed in 4 h. The assay sensitivity was 0·03 μg/l, and a normal range of 0·05 to 0·22 μg/l was established. In a retrospective study, elevated circulating glycoprotein α-subunit was detected in 22% of patients with non-functioning pituitary tumours previously treated with surgery and/or radiotherapy.
Journal of Endocrinology (1993) 136, 511–516
MONOCLONAL ANTIBODY ENHANCEMENT OF FSH-INDUCED UTERINE GROWTH IN SNELL DWARF MICE
Authors: Glencross R. G. , Lovell R. D. , Holder A. T. 
Published: December 2008

ABSTRACT
The enhancing effect of bovine FSH monoclonal antibody (bFSH-MAb) on the gonadotrophic activity of FSH was investigated in dwarf mice using a uterine weight bioassay.
Increasing doses of bovine FSH (NIH-FSH-B1; 3.3, 10 or 30 μg/day) were administered for 5 days to dwarf mice (groups of five) with or without administration of a bFSH-MAb preparation (USDA-bFSH-MC28; 100 μg protein/day) which at a dilution of 1:15 000 bound 50% of 125I-labelled bFSH (USDA-bFSH-BP3). The bFSH, at the doses given, gave no increases in uterine weight; when, however, these doses were given with bFSH-MAb, significant (three- to four fold) increases in uterine weight resulted.
Benzodiazepine antagonism of thyrotrophin-releasing hormone receptors: biphasic actions on growth hormone secretion in domestic fowl
Authors: Harvey S. 
Published: December 2008

ABSTRACT
Benzodiazepines are pharmacological agents widely used for their anxiolytic and anticonvulsant properties. However, as these drugs are known to antagonize the binding and action of thyrotrophin-releasing hormone (TRH) in pituitary tissue, the possibility that they may modulate GH secretion was investigated in domestic fowl, in which TRH is a GH-releasing factor. Chlordiazepoxide (an antagonist of central-type benzodiazepine receptors) had no significant effect on the basal release of GH from incubated chicken pituitary glands, but at concentrations > 10 μmol/l chlordiazepoxide suppressed somatotroph responsiveness and sensitivity to TRH stimulation. At this concentration, chlordiazepoxide competitively displaced the binding of [3H]3-methyl-histidine2-TRH ([3H]Me-TRH) to chicken pituitary membranes. The prior incubation of pituitary glands with chlordiazepoxide had no significant effect on the number of [3H]Me-TRH-binding sites, which were also unaffected by the administration of chlordiazepoxide in vivo. However, contrary to its effects in vitro, chlordiazepoxide reduced basal GH secretion in vivo, whilst potentiating the GH response to systemic TRH challenge. These results demonstrate benzodiazepine antagonism of TRH-binding sites in domestic fowl and a biphasic modulation of GH secretion, which may be mediated through opposing actions at pituitary and central sites.
Journal of Endocrinology (1993) 137, 35–42
Activin A inhibits cell-cycle progression induced by insulin-like growth factor-I in Balb/c 3T3 cells
Authors: Kojima I. , Mogami H. , Kawamura N. , Shibata H. 
Published: December 2008

ABSTRACT
The present study was carried out to examine the effect of activin A on cell-cycle progression induced by insulin-like growth factor-I (IGF-I) in Balb/c 3T3 cells. When activin A was added together with IGF-I to competent cells primed with epidermal growth factor (primed competent cells), both [3H]thymidine incorporation and nuclear labelling induced by IGF-I were inhibited. The inhibition was concentration-dependent and the maximum inhibition was obtained with 1 nmol activin A/l. To ascertain the time in which activin A exerted its inhibitory action, we divided 12 h, the time required for primed competent cells to progress towards the S phase, into four periods and activin A was added during each of the four periods. It was effective when added during either the second (3 to 6 h) or the third period (6 to 9 h) but it did not affect cell-cycle progression when added during the first (0 to 3 h) or the last period (9 to 12 h). We then examined whether activin A affected intracellular events elicited by IGF-I. It did not affect either autophosphorylation of the IGF-I receptor or calcium entry induced by IGF-I. Likewise, it did not cause any change in the radioactivity of 1,2-diacylglycerol (DAG) in cells prelabelled with [3H]myristate while the increase in the mass of DAG induced by IGF-I was markedly reduced by activin A. The dose-response relationship for the activin A-mediated reduction of DAG mass correlated well with that for the activin A-mediated reduction of DNA synthesis. Activin A was effective in reducing DAG mass even when added 3 h after the addition of IGF-I. These results indicate that activin A attenuates cell-cycle progression in the middle of the G1 phase. The results also raise the possibility that reduction of DAG mass may account for the inhibitory effect of activin A on cell-cycle progression.
Journal of Endocrinology (1993) 137, 99–105
ACTH secretion from isolated hypophysial anterior lobes of male and female newborn rats: effects of corticotrophin-releasing factor, arginine vasopressin and oxytocin alone or in combination
Authors: Hary L. , Dupouy J. P. , Chatelain A. 
Published: December 2008

ABSTRACT
ACTH release by the anterior pituitary lobes of 8-day-old newborn rats (males and females) in the presence of rat corticotrophin-releasing factor (rCRF), arginine vasopressin (AVP) and oxytocin, given alone or in association, was measured in vitro. Rat CRF and AVP induced a dose-dependent release of ACTH in both sexes, while oxytocin was unable to stimulate ACTH secretion except at the highest dose tested. No sex-related difference was noted for any of the responses.
Oxytocin (1 nmol/l) potentiated the response to rCRF (0·20 nmol/l) by the anterior pituitary lobes of females but not by those of males. This oxytocin potentiation was abolished when female newborn rats were injected at birth with testosterone (1 mg). AVP (1 nmol/l) alone stimulated ACTH release from the anterior pituitary lobes of the newborn rats of both sexes and markedly potentiated the ACTH response to rCRF.
Although no difference between the sexes was noted for basal levels of AVP and oxytocin in the hypothalamus, the neurointermediate lobe and the peripheral plasma, the present data on the sex-related effect of oxytocin on the newborn adenohypophysis could, in part, explain why ACTH release in response to ether stress was previously reported to be more lasting in females than in males on day 8 postpartum.
Journal of Endocrinology (1993) 137, 123–132
A novel method for the extraction of sheep insulin-like growth factors-I and -II from plasma prior to radioimmunoassay
Authors: Moore L. G. , Mylek M. E. 
Published: December 2008

ABSTRACT
The measurement of insulin-like growth factors (IGFs) in plasma is complicated by the presence of high-affinity IGF-binding proteins (IGFBPs). Consequently, the IGFBPs need to be removed or their IGF-binding effects need to be neutralized prior to assaying samples for IGFs. It was observed that IGFs but not IGFBPs from sheep plasma bind to the size-exclusion gel Sephacryl S-100 HR at a low pH and that the IGFs can subsequently be eluted off at a neutral pH. From this observation a convenient method was developed for the extraction from plasma of ovine (o) IGF-I and -II free from detectable IGFBPs with close to 100% recovery. When assayed in homologous sheep IGF-I and -II radioimmunoassays the Sephacryl-extracted plasma samples gave dose–response curves which were parallel to purified oIGFs. Furthermore, the results obtained by Sephacryl extraction were highly correlated with those found by the established Sephadex G-75 extraction procedure.
Journal of Endocrinology (1993) 137, 239–245
Effects of thyroxine on avian moulting may not involve prior conversion to tri-iodothyronine
Authors: Pant K. , Chandola-Saklani A. 
Published: December 2008

ABSTRACT
The comparative effects of equimolar doses of thyroxine (T4) and tri-iodothyronine (T3) and of the inhibition of peripheral monodeiodination were studied on feather regeneration and moult in thyroidectomized and intact adult male spotted munia (Lonchura punctulata). T4 was significantly more effective than T3 at all dose levels in inducing feather regeneration in thyroidectomized birds. Suppression of mono-deiodination by iopanoic acid (IOP) was not accompanied by a suppression of T4-induced feather regeneration in thyroidectomized birds and IOP alone was without effect in thyroidectomized birds. Long-term treatment of intact birds with IOP accelerated the process of moulting by about 3 months. These findings question the prevailing concept that T3 is the finally active biological compound and T4 a mere precursor.
Journal of Endocrinology (1993) 137, 265–270
Secretion of 19-hydroxyandrostenedione and 19-hydroxytestosterone by porcine Leydig cells in vitro and in vivo
Authors: Raeside J. I. , Renaud R. L. , Friendship R. M. , Khalil M. W. 
Published: December 2008

ABSTRACT
19-Hydroxytestosterone and 19-hydroxyandrostenedione have been identified as secretory products of the testes in the mature male domestic pig. Their isolation and identification were made by reverse-phase high-performance liquid chromatography and capillary gas chromatography-mass spectrometry (CGC-MS) of extracts from testicular vein blood and media of incubations with Leydig cells. Blood was collected from veins on the surface of the testes of anaesthetized boars. Collagenase-dispersed Percoll-purified cells (> 90% pure) were incubated (20 × 106 cells/flask) with androstenedione (8·75 μmol/l) or [3H]androstenedione (5 × 106 c.p.m.) for < 60 min. Steroids were recovered from plasma or media by solid-phase extraction and the unconjugated fractions chromatographed isocratically in two solvent systems (acetonitrile: water, 37:63 (v/v) and methanol: water, 70:30 (v/v)) before CGC-MS analysis. 19-Hydroxy-testosterone was present in greater quantities than 19-hydroxyandrostenedione in testicular vein blood; it was also seen as a quantitatively significant metabolite of unlabelled and radioactive androstenedione in the incubation studies. The demonstration of the secretion of 19-hydroxyandrogens from porcine testes thus raises questions concerning the physiological significance of a testicular, rather than an adrenal, secretion of these compounds.
Journal of Endocrinology (1993) 137, 281–289
Patterns of neurohypophysial hormone release during dehydration in the rat
Authors: Windle R. J. , Forsling M. L. , Smith C. P. , Balment R. J. 
Published: December 2008

ABSTRACT
A study was performed investigating the daily patterns of hormone release accompanying changes in fluid balance in the male rat during 48 h of dehydration. The blood volume decreased by 18%, the largest change occurring during the initial period when the rats showed an effective loss of body sodium. During the second day of dehydration, sodium retention was again seen. Plasma sodium concentrations showed a progressive increase, the total rise being 5–6%; the greatest changes were seen during the dark phases of the cycle which may be due to the nocturnal food intake.
Plasma vasopressin and oxytocin concentrations were significantly elevated throughout dehydration to levels which could be reproduced by acutely increasing plasma sodium and decreasing blood volume to the same extent. The observed increases were influenced by the phase of the day–night cycle, being greatest over the dark phases of the cycle. The overall increases were greatest when dehydration commenced at the start of the dark phase. Dehydration initially led to a rise in plasma corticosterone concentrations, whilst plasma concentrations of atrial natriuretic peptide were decreased. Plasma angiotensin II concentrations rose significantly during the later period of sodium retention.
Journal of Endocrinology (1993) 137, 311–319
The effect of cortisol on the secretion of ACTH by anterior pituitary cells of the horse in culture
Authors: Evans M. J. , Kitson N. E. , Livesey J. H. , Donald R. A. 
Published: December 2008

ABSTRACT
Perifused equine anterior pituitary cells were used to investigate the effect of cortisol on the ACTH response to pulses of corticotrophin-releasing hormone (CRH; 0·01 nmol/l) and arginine vasopressin (AVP; 100 nmol/l), given for 5 min every 30 min for 690 min and ACTH measured in 5-min fractions. At the fourth pulse of secretagogue (0 min), a constant perifusion with cortisol began (0 nmol/l (control), 100, 200, 500, 5000 and 50 000 nmol/l) and continued until the ninth pulse (150 min). For each pulse of secretagogue, the amount of ACTH (pmol) secreted in response to each pulse (ACTH response area), the highest concentration of ACTH (μg/l) measured after each pulse (peak height) and the mean ACTH in the three prepulse fractions (ACTH baseline) were determined. Data from control columns in each experiment were fitted by least squares to an exponential function to produce a mean control value for each end-point; results in all columns were expressed as a percentage of the mean control values.
The addition of cortisol had a highly significant negative effect on ACTH response area, peak height and baseline at all times from + 30 to + 240 min (columns given cortisol compared with the mean of control column values by t-test). Analysis of variance of the data showed that the higher the cortisol concentration, the quicker the ACTH response area (P = 0·0072) and peak height (P = 0·002) decreased to < 50% of mean control, and the greater the maximum percentage change (suppression) in ACTH response area (P <0·0001) and peak height (P <0·0001). The maximum percentage change (suppression) in base-line was independent of cortisol concentration.
At + 30 min after the start of cortisol perifusion, the ACTH response area in CRH columns was significantly lower than in AVP columns (P = 0·0088), and remained lower 90 min after the end of perifusion (P = 0·0084) but the maximum percentage change (suppression) was not different between secretagogues. ACTH peak height was significantly (P < 0·0268) lower in CRH than in AVP columns (from + 30 min until 180 min after the end of cortisol perifusion) and the maximum percentage change (suppression) was also greater (P = 0·0011) in CRH columns.
This study shows the effect of different concentrations of cortisol on CRH- and AVP-induced ACTH secretion by equine anterior pituitary cells, and the time-course for ACTH responses to be inhibited by, and recover from, cortisol perifusion. The highly significant inhibitory effect of cortisol on stimulated ACTH secretion was more apparent when CRH was the secretagogue than when AVP was the secretagogue. The significant inhibitory effect of cortisol on unstimulated baseline secretion of ACTH has not been described previously. These effects occur at physiological concentrations of secretagogues and cortisol. This suggests that, in vivo, circulating cortisol may have an important role in the control of ACTH secretion at pituitary level.
Journal of Endocrinology (1993) 137, 403–412
The inhibitory effect of noradrenaline on thyrotrophin-stimulated 3,5,3′-tri-iodothyronine and thyroxine release is mediated through a Ca2+-dependent process in the thyroid gland of the mouse
Authors: Oda Y. , Mashita K. , Mori-Tanaka M. , Kitajima K. , Miyagawa J. , Tajima K. , Hanafusa T. , Kono N. , Matsuzawa Y. 
Published: December 2008

ABSTRACT
We examined the effect of noradrenaline on the release of 3,5,3′-tri-iodothyronine (T3) and thyroxine (T4) from perifused mouse thyroid. Noradrenaline suppressed the thyrotrophin (TSH)-stimulated release of T3 and T4. The addition of prazosin, which is a specific α1 antagonist, or the depletion of Ca2+ from the perifusion buffer completely abolished the inhibitory effect of noradrenaline on TSH-stimulated T3 and T4 release. Noradrenaline did not inhibit TSH-stimulated cyclic adenosine 3′,5′-monophosphate (cAMP) release in the presence of 3-isobutyl-1-methylxanthine (IBMX), which inhibits both cAMPspecific and calmodulin-sensitive phosphodiesterases. Noradrenaline significantly suppressed the TSH-stimulated release of T3 and T4 in the presence of IBMX. These results suggest that the inhibitory effect of noradrenaline on TSH-stimulated T3 and T4 release is not mediated through a cAMP-dependent process or the activation of a calmodulin-sensitive phosphodiesterase, and that this inhibition is mediated through a Ca2+-dependent process regulated by the α1-adrenergic system in the mouse thyroid.
Journal of Endocrinology (1993) 138, 73–80
Presence of growth hormone-binding proteins in cattle plasma and milk
Authors: Devolder A. , Renaville R. , Sneyers M. , Callebaut I. , Massart S. , Goffinet A. , Burny A. , Portetelle D. 
Published: December 2008

ABSTRACT
The presence of GH-binding proteins (GHBPs) in the plasma of adult cattle was investigated using Sephadex G-200 filtration, Western ligand blotting and Western blotting. The changes in the concentration of GHBP in the plasma of dairy half-sister heifers during the first year of life as well as the presence of GHBP in milk were also investigated. When analytical chromatography (on a 1·6 × 100 cm column) was performed, five peaks of recombinant bovine GH (rbGH)-associated radioactivity were revealed in cattle plasma; the first peak, which appeared near the void volume, was presumed to represent aggregates, the second (Mr 290 kDa) and the third peaks (Mr 75 kDa) corresponded to specific rbGH–GHBP complexes; the last two peaks representing free 125I-labelled rbGH and Na[125I]. Western ligand blotting revealed multiple GHBPs. Three major bands were observed at approximately 190, 58 and 31 kDa; an excess of unlabelled hormone blocked the binding of 125I-labelled rbGH. Minor non-specific binding bands were also detected in cattle plasma with molecular weights between 40 and 136 kDa. One monoclonal antibody (8H7) produced against synthetic peptide (amino acids 54–63 of the extracellular domain of the bovine GH receptor) specifically interacted with 190 and 58 kDa bands while the 31 kDa band was not recognized. Finally, Western ligand blots were performed to evaluate the changes in plasma GHBP during the first year of life in 55 dairy half-sister heifers and to identify GHBP in milk. In plasma, the intensity of the 31 kDa band varied greatly between animals while the other specific bands remained stable. In milk, all specific GHBP bands observed by Western ligand blotting disappeared a few days after parturition. In conclusion, these results demonstrate the presence of GHBPs in cattle plasma and milk. There were important variations in GHBP between dairy halfsister heifers during the first year of life but the potential role of these binding proteins in the regulation of the biological activity of GH in ruminants and their functions in milk remain to be determined.
Journal of Endocrinology (1993) 138, 91–98
Radioimmunoassay of mouse vas deferens protein: developmental profile and hormonal regulation
Authors: Martinez A. , Berger M. , Jean-Faucher Ch. , Veyssière G. , Jean Cl. 
Published: December 2008

ABSTRACT
This study investigated the hormonal regulation of the developmental pattern of a major protein of the mouse vas deferens (MVDP) which represents 10% of the vas deferens protein content. Using a specific radioimmunoassay, MVDP was first detected in 10-day-old males and its concentration increased sharply between 10 and 30 days, reaching adult levels at 40 days. In adult males, MVDP disappeared after castration, and testosterone treatment for 15 days was necessary to reverse the effect of castration completely. In 10-day-old mice castrated at birth, MVDP levels were similar to those measured in controls of the same age. Testosterone administration from 1 to 10 days of age did not induce precocious accumulation of MVDP. These results suggested that the neonatal expression of MVDP is independent of androgens. From 10 to 30 days, the increase in MVDP levels was androgen-dependent as shown by the castration and injection experiments. In males castrated at birth, the androgen-induced accumulation of MVDP was greatly reduced in adulthood. This suggested that neonatal androgens are necessary to obtain full expression of the MVDP gene in adults.
Journal of Endocrinology (1993) 138, 99–105
Insulin-like growth factor-II and transforming growth factor-α in developing human fetal pancreatic islets
Authors: Miettinen P. J. , Otonkoski T. , Voutilainen R. 
Published: December 2008

ABSTRACT
To understand the development of the human pancreas better, we studied the expression and regulation of insulin, insulin-like growth factor-II (IGF-II) and transforming growth factor-α (TGF-α) genes in the human fetal pancreas and islet-like cell clusters (ICC) from the second trimester human fetuses. Northern blot analysis revealed an abundant expression of IGF-II, insulin and TGF-α mRNAs in the intact pancreas and the cultured ICCs. Furthermore, transcripts for insulin receptor, type-1 and -2 IGF receptors, and GH receptor could be amplified by polymerase chain reaction analysis from the pancreas and the ICCs. With in-situ hybridization, IGF-II mRNA was found in abundance in both the exocrine and endocrine pancreas, exceeding the amount of insulin mRNA. In ICCs, insulin mRNA-containing cells were present as small clusters in the periphery and in the centre of the clusters corresponding to the immunolocation of insulin. The ICCs also contained many epidermal growth factor-, insulin- and type-1 IGF receptor- and TGF-α-positive cells.
When the ICCs were cultured in the presence of various secretagogues, only dibutyryl cyclic AMP was found to up-regulate insulin mRNA (39%; P < 0·05). IGF-II mRNA was also under cyclic AMP-dependent regulation (threefold increase; P = 0·025). Furthermore, blocking the type-1 IGF receptor with a monoclonal receptor antibody drastically reduced insulin expression (87%; P = 0·005) and additionally down-regulated IGF-II mRNA (49%; P = 0·005). IGF-1, IGF-II, TGF-α or epidermal growth factor-receptor antibody had no significant effect on either insulin or IGF-II mRNA. Exogenous TGF-α inhibited the release of insulin by the ICCs. It was concluded that IGF-II and TGF-α may be involved in the regulation of islet growth and differentiation.
Journal of Endocrinology (1993) 138, 127–136