bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twenty-One Day Administration of Dienogest Reversibly Suppresses Gonadotropins and Testosterone in Normal Men
Authors: Meriggiola M. Cristina , Bremner William J. , Costantino Antonietta , Bertaccini Alessandro , Morselli-Labate Antonio Maria , Huebler Doris , Kaufmann Guenter , Oettel Michael , Flamigni Carlo 
Published: January 2014

Androgen-progestin combinations are promising male contraceptive regimens. Optimization of these regimens includes the development of new progestins with more favorable biological properties. In this context we tested the effects of the progestin dienogest (DNG) on reproductive hormones and metabolic parameters in men.After a 3-wk control period, 25 men were randomly assigned to receive daily doses of 2, 5, or 10 mg DNG or placebo and 10 mg cyproterone acetate for 21 d (n = 5 subjects/group). Subjects were followed for 2 wk after cessation of hormone administration. Weekly blood samples, physical examinations, hormone and chemistry measurements, semen analysis, and sexual/behavioral assessments were performed. These parameters were compared among study groups and within each group at different time points throughout the study periods.DNG and cyproterone acetate administration resulted in profound suppression of gonadotropins and T with no change in SHBG levels. No adverse effects were detected in any subject. Hormone levels returned to baseline after stopping hormone intake.DNG is a potent suppressor of gonadotropins and T in men and does not induce adverse effects over a 21-d administration. DNG is a promising progestin to be used in clinical trials for male contraception.
Marked Disproportionality in Bone Size and Mineral, and Distinct Abnormalities in Bone Markers and Calcitropic Hormones in Adult Turner Syndrome: A Cross-Sectional Study
Authors: Gravholt Claus Højbjerg , Lauridsen Anna Lis , Brixen Kim , Mosekilde Leif , Heickendorff Lene , Christiansen Jens Sandahl 
Published: January 2014

Most women with Turner syndrome (TS) have no gonadal activity and thus lack estrogen. Bone mineral density (BMD) is often reduced, leading to an increased risk of osteoporosis and fractures. However, growth retardation with reduced final height and other endocrine disturbances may compromise interpretation of skeletal measurements. The aim of the present study was to explore skeletal findings, bone metabolism, and calcium homeostasis in TS. Sixty women with TS (age, 37 ± 9 yr) and 181 normal age-matched female controls were studied. Bone area (A; square centimeters), bone mineral content (BMC; grams), area-adjusted BMD (aBMD; grams/square centimeter), and volumetric BMD (vBMD; grams/cubic centimeter) were measured at lumbar spine, femoral neck, and forearm using dual energy x-ray absorptiometry. Twenty-eight percent had osteopenia, and 23% had osteoporosis, according to World Health Organization criteria. At the lumbar spine, A, BMC, aBMD, and vBMD were reduced by 18, 27, 11, and 6%, respectively; at the femoral neck, A, BMC, and aBMD were reduced by 2, 10, and 8%, respectively, whereas the 9% reduction in vBMD was insignificant (P = 0.07); and in the forearm, A, BMC, and aBMD were reduced by 53, 55, and 9%, respectively. Bone markers indicated an enhanced bone resorption (21 and 23% increase in C-terminal and N-terminal cross-linking telopeptides of type I collagen/creatinine, respectively) with unchanged (osteocalcin, procollagen I N-terminal propeptide) or reduced (54% reduction in bone alkaline phosphatase) bone formation. Plasma levels of calcium and 25-hydroxyvitamin D (26%) were reduced, and PTH levels increased (74%) in TS. IGF-I (30%), IGF binding protein 3 (18%), testosterone (50%), and SHBG (40%) were reduced in TS.
In summary, A, BMC, and aBMD were found to be universally reduced in TS, whereas vBMD was slightly reduced in the spine. Increased resorption of bone was present, with normal or blunted bone formation, suggesting uncoupling or imbalance in bone remodeling. Skeletal changes may be induced by chromosome abnormalities or by secondary endocrine or metabolic changes related to a relative estrogen deficiency, testosterone deficiency, reduced IGF-I, low vitamin D status, and secondary hyperparathyroidism.
Expression of PAX8-PPARγ1 Rearrangements in Both Follicular Thyroid Carcinomas and Adenomas
Authors: Marques Ana Rita , Espadinha Carla , Catarino Ana L. , Moniz Sónia , Pereira Teresa , Sobrinho Luís G. , Leite Valeriano 
Published: January 2014

Recently, a translocation t(2;3)(q13;p25), leading to the formation of a chimeric PAX8-peroxisome proliferator-activated receptor (PPAR)γ1 oncogene, was detected in follicular thyroid carcinomas (FTC), but not in follicular thyroid adenomas (FTA), papillary thyroid carcinomas (PTC), or multinodular hyperplasias. However, previous cytogenetic studies have identified the t(2;3)(q13;p25) translocation also in some cases of FTA. In this study, we have combined RT-PCR with primers in exons 4–8 of PAX8 and in exon 1 of PPARγ1 with PPARγ immunohistochemistry to study PAX8-PPARγ1 oncogene activation in FTC (n = 9), FTA (n = 16), PTC (n = 9), anaplastic thyroid carcinomas (n = 4), and multinodular hyperplasias (n = 2). PAX8-PPARγ1 rearrangements were detected by RT-PCR in 5 of 9 (56%) FTC and in 2 of 16 (13%) FTA. By contrast, all cases of PTC, anaplastic thyroid carcinomas, and multinodular hyperplasia were RT-PCR-negative. Diffuse nuclear immunoreactivity for PPARγ was observed in 7 of 9 (78%) FTC, 5 of 16 FTA (31%), and 1 of 9 PTC (11%). Positivity was focal in 3 cases (1 FTC, 1 PTC, and 1 multinodular hyperplasia). Diffuse nuclear staining for PPARγ was present in RT-PCR- negative cases of FTC (n = 3), FTA (n = 3), and PTC (n = 1), suggesting that a different PAX8-PPARγ1 breakpoint, a rearrangement between PPARγ1 and a non-PAX8 partner, or overexpression of the native protein might be present.
Our findings that PAX8-PPARγ1 rearrangements are present in both follicular carcinomas and adenomas suggest that this oncogene is not a reliable marker to differentiate between FTC and FTA in fine-needle aspiration biopsies of follicular neoplasms of the thyroid.
A Mutation in the Follicle-Stimulating Hormone Receptor as a Cause of Familial Spontaneous Ovarian Hyperstimulation Syndrome
Authors: Montanelli Lucia , Delbaere Anne , Di Carlo Costantino , Nappi Carmine , Smits Guillaume , Vassart Gilbert , Costagliola Sabine 
Published: January 2014

Abstract
Ovarian hyperstimulation syndrome (OHSS) occurs mainly after excessive stimulation of the ovaries by exogenous gonadotropins administrated in the context of in vitro fertilization procedures (iatrogenic OHSS). Recently, spontaneous and recurrent occurrence of the disease (spontaneous OHSS) was shown in two families to be caused by mutations affecting the follitropin receptor (FSHr). The two mutant FSHr (T449I, D567N) harbor aminoacid substitutions in the serpentine portion of the receptor and display abnormally high sensitivity to the pregnancy hormone hCG, thus providing a satisfactory explanation to the phenotype. In addition, mutant D567N showed also increased sensitivity to thyrotopin (TSH) and displayed increase in basal (ligand-independent) activity. In this report, we describe a new familial case of recurrent OHSS. The affected women were heterozygous for a different mutation involving codon 449, where an alanine was substituted for threonine. Similar to D567N, the T449A FSHr mutant shows an increase of its sensitivity to both hCG and TSH, together with an increase in basal activity. Together with the two previous studies, this report shows that inappropriate stimulation of the FSHr by hCG is a cause of spontaneous OHSS.
Expression and Characterization of Recombinant Type 2 3α-Hydroxysteroid Dehydrogenase (HSD) from Human Prostate: Demonstration of Bifunctional 3α/17β-HSD Activity and Cellular Distribution
Authors: Lin Hsueh-Kung , Jez Joseph M. , Schlegel Brian P. , Peehl Donna M. , Pachter Jonathan A. , Penning Trevor M. 
Published: January 2014

AbstractIn androgen target tissues, 3α-hydroxysteroid dehydrogenase (3α-HSD) may regulate occupancy of the androgen receptor (AR) by catalyzing the interconversion of 5α-dihydrotestosterone (5α-DHT) (a potent androgen) and 3α-androstanediol (a weak androgen). In this study, a 3α-HSD cDNA (1170 bp) was isolated from a human prostate cDNA library. The human prostatic 3α-HSD cDNA encodes a 323-amino acid protein with 69.9%, 84.1%, 99.4%, and 87.9% sequence identity to rat liver 3α-HSD and human type 1, type 2, and type 3 3α-HSDs, respectively, and is a member of the aldo-keto reductase superfamily. The close homology with human type 2 3α-HSD suggests that it is either identical to this enzyme or a structural allele. Surprisingly, when the recombinant protein was expressed and purified from Escherichia coli, the enzyme did not oxidize androsterone when measured spectrophotometrically, an activity previously assigned to recombinant type 2 3α-HSD using this assay. Complete kinetic characterization of the purified protein using spectrophotometric, fluorometric, and radiometric assays showed that the catalytic efficiency favored 3α-androstanediol oxidation over 5α-DHT reduction. Using[ 14C]-5α-DHT as substrate, TLC analysis confirmed that the reaction product was[ 14C]-3α-androstanediol. However, in the reverse reaction, [3H]-3α-androstanediol was oxidized first to [3H]-androsterone and then to [3H]-androstanedione, revealing that the expressed protein possessed both 3α- and 17β-HSD activities. The 17β-HSD activity accounted for the higher catalytic efficiency observed with 3α-androstanediol. These findings indicate that, in the prostate, type 2 3α-HSD does not interconvert 5α-DHT and 3α-androstanediol but inactivates 5α-DHT through its 3-ketosteroid reductase activity. Levels of 3α-HSD mRNA were measured in primary cultures of human prostatic cells and were higher in epithelial cells than stromal cells. In addition, elevated levels of 3α-HSD mRNA were observed in epithelial cells derived from benign prostatic hyperplasia and prostate carcinoma tissues. Expression of 3α-HSD was not prostate specific, since high levels of mRNA were also found in liver, small intestine, colon, lung, and kidney. This study is the first complete characterization of recombinant type 2 3α-HSD demonstrating dual activity and cellular distribution in the human prostate.
Isolation and Characterization of a Pituitary Tumor-Transforming Gene (PTTG)
Authors: Pei Lin , Melmed* Shlomo 
Published: January 2014

Abstract
Pathogenesis of tumor formation in the anterior pituitary has been intensively studied, but the common mechanism involved in pituitary cell transformation and tumorigenesis remains elusive. In this study, we used mRNA differential display PCR to identify mRNAs that are differentially expressed in rat pituitary tumor cells compared with normal pituitary tissue. An mRNA exclusively expressed in pituitary tumor but not in normal pituitary was characterized. Using this pituitary tumor-specific PCR product as a probe to screen a cDNA library constructed from rat pituitary tumor GH4 cells, a cDNA of 974 bp was isolated. This cDNA encodes a novel protein of 199 amino acids, which contains no well characterized functional motifs. The mRNA of this cDNA is detected in normal adult testis and in embryonic liver, where the transcript is about 300 bp shorter and expressed at a much lower level than that detected from pituitary tumor cells. Overexpression of this protein in mouse 3T3 fibroblasts shows that it inhibits cell proliferation and induces cell transformation in vitro. Injection of transfected 3T3 cells into athymic nude mice resulted in tumor formation within 3 weeks in all animals. These results indicate that pituitary tumor cells express a unique and potent transforming gene (PTTG), which may play a role in pituitary tumorigenesis.
Angiotensin II and Potassium Regulate Human CYP11B2 Transcription through Common cis-Elements
Authors: Clyne Colin D. , Zhang Yin , Slutsker Liliya , Mathis J. Michael , White Perrin C. , Rainey William E. 
Published: January 2014

AbstractAldosterone synthase is a mitochondrial enzyme that catalyzes the conversion of 11-deoxycorticosterone to the potent mineralocorticoid aldosterone. The gene encoding aldosterone synthase, CYP11B2, is expressed in the zona glomerulosa of the adrenal cortex. Although the major physiological regulators of aldosterone production are angiotensin II (ANG II) and potassium (K+), the mechanisms by which these compounds regulate CYP11B2 transcription are unknown. Therefore we analyzed the human CYP11B2 5′-flanking region using a transient transfection expression system in the H295R human adrenocortical cell line. ANG II and K+ increased expression of a luciferase reporter construct containing 2015 bp of human CYP11B2 5′-flanking DNA. This response was mimicked by treatment with the calcium channel activator BAYK8644, whereas activation of the protein kinase C pathway with 12-o-tetradecanoylphorbol-13-acetate had no effect. Reporter gene activity was also increased after activation of cAMP-dependent pathways by (Bu)2cAMP. Deletion, mutation, and deoxyribonuclease I footprinting analyses of the CYP11B2 5′-flanking region identified two distinct elements at positions −71/−64 (TGACGTGA) and −129/−114 (CTCCAGCCTTGACCTT) that were both required for full basal reporter gene activity and for maximal induction by either cAMP or calcium-signaling pathways. The −71/−64 element, which resembles a consensus cAMP response element (CRE), bound CRE-binding proteins from H295R cell nuclear extracts as determined by electrophoretic mobility shift analysis. Analysis of the −129/−114 element using electrophoretic mobility shift analysis demonstrated binding of the orphan nuclear receptors steroidogenic factor 1 and chicken ovalbumin upstream promoter transcription factor. These data demonstrate that ANG II, K+, and cAMP-signaling pathways utilize the same SF-1 and CRE-like cis-elements to regulate human CYP11B2 expression.
Cross-Talk between Nuclear Factor-κB and the Steroid Hormone Receptors: Mechanisms of Mutual Antagonism
Authors: McKay Lorraine I. , Cidlowski John A. 
Published: January 2014

AbstractNuclear factor κB (NF-κB) is an inducible transcription factor that positively regulates the expression of proimmune and proinflammatory genes, while glucocorticoids are potent suppressors of immune and inflammatory responses. NF-κB and the glucocorticoid receptor (GR) physically interact, resulting in repression of NF-κB transactivation. In transient cotransfection experiments, we demonstrate a dose-dependent, mutual antagonism between NF-κB and GR. Functional dissection of the NF-κB p50 and p65 subunits and deletion mutants of GR indicate that the GR antagonism is specific to the p65 subunit of NF-κB heterodimer, whereas multiple domains of GR are essential to repress p65-mediated transactivation. Despite its repression of GR transactivation, p65 failed to block the transrepressive GR homologous down-regulation function. We also demonstrate that negative interactions between p65 and GR are not selective for GR, but also occur between NF-κB and androgen, progesterone B, and estrogen receptors. However, although each of these members of the steroid hormone receptor family is repressed by NF-κB, only GR effectively inhibits p65 transactivation. Further, in cotransfections using a chimeric estrogen-GR, the presence of the GR DNA-binding domain is insufficient to confer mutual antagonism to the p65-estrogen receptor interaction. Selectivity of p65 repression for each steroid receptor is demonstrated by IκB rescue from NF-κB-mediated inhibition. Together these data suggest that NF-κB p65 physically interacts with multiple steroid hormone receptors, and this interaction is sufficient to transrepress each steroid receptor. Further, the NF-κB status of a cell has the potential to significantly alter multiple steroid signaling pathways within that cell.
Structural Requirements for the Activation of the Human Growth Hormone Secretagogue Receptor by Peptide and Nonpeptide Secretagogues
Authors: Feighner Scott D. , Howard Andrew D. , Prendergast Kristine , Palyha Oksana C. , Hreniuk Donna L. , Nargund Ravi , Underwood Dennis , Tata James R. , Dean Dennis C. , Tan Carina P. , McKee Karen Kulju , Woods John W. , Patchett Arthur A. , Smith Roy G. , Van der Ploeg Lex H. T. 
Published: January 2014

AbstractAntibodies raised against an intracellular and extracellular domain of the GH secretagogue receptor (GHS-R) confirmed that its topological orientation in the lipid bilayer is as predicted for G protein-coupled receptors with seven transmembrane domains. A strategy for mapping the agonist-binding site of the human GHS-R was conceived based on our understanding of ligand binding in biogenic amine and peptide hormone G protein-coupled receptors. Using site-directed mutagenesis and molecular modeling, we classified GHS peptide and nonpeptide agonist binding in the context of its receptor environment. All peptide and nonpeptide ligand classes shared a common binding domain in transmembrane (TM) region 3 of the GHS-R. This finding was based on TM-3 mutation E124Q, which eliminated the counter-ion to the shared basic N+ group of all GHSs and resulted in a nonfunctional receptor. Restoration of function for the E124Q mutant was achieved by a complementary change in the MK-0677 ligand through modification of its amine side-chain to the corresponding alcohol. Contacts in other TM domains [TM-2 (D99N), TM-5 (M213K, S117A), TM-6 (H280F), and extracellular loop 1 (C116A)] of the receptor revealed specificity for the different peptide, benzolactam, and spiroindolane GHSs. GHS-R agonism, therefore, does not require identical disposition of all agonist classes at the ligand-binding site. Our results support the hypothesis that the ligand-binding pocket in the GHS-R is spatially disposed similarly to the well characterized catechol-binding site in theβ 2-adrenergic receptor.
Tissue-Specific Imprinting of the Mouse Insulin-Like Growth Factor II Receptor Gene Correlates with Differential Allele-Specific DNA Methylation
Authors: Hu Ji-Fan , Oruganti Haritha , Vu Thanh H. , Hoffman Andrew R. 
Published: January 2014

AbstractImprinted genes may be expressed uniparentally in a tissue- and development-specific manner. The insulin-like growth factor II receptor gene (Igf2r), one of the first imprinted genes to be identified, is an attractive candidate for studying the molecular mechanism of genomic imprinting because it is transcribed monoallelically in the mouse but biallelically in humans. To identify the factors that control genomic imprinting, we examined allelic expression of Igf2r at different ages in interspecific mice. We found that Igf2r is not always monoallelically expressed. Paternal imprinting of Igf2r is maintained in peripheral tissues, including liver, kidney, heart, spleen, intestine, bladder, skin, bone, and skeletal muscle. However, in central nervous system (CNS), Igf2r is expressed from both parental alleles. Southern analysis of the Igf2r promoter (region 1) revealed that, outside of the CNS where Igf2r is monoallelically expressed, the suppressed paternal allele is fully methylated while the expressed maternal allele is completely unmethylated. In CNS, however, both parental alleles are unmethylated in region 1. The importance of DNA methylation in the maintenance of the genomic imprint was also confirmed by the finding that Igf2r imprinting was relaxed by 5-azacytidine treatment. The correlation between genomic imprinting and allelic Igf2r methylation in CNS and other tissues thus suggests that the epigenetic modification in the promoter region may function as one of the major factors in maintaining the monoallelic expression of Igf2r.
Insulin-Like Growth Factor-I Affects Perinatal Lethality and Postnatal Development in a Gene Dosage-Dependent Manner: Manipulation Using the Cre/loxP System in Transgenic Mice
Authors: Liu Jun-Li , Grinberg Alexander , Westphal Heiner , Sauer Brian , Accili Domenico , Karas Michael , LeRoith Derek 
Published: January 2014

AbstractInsulin-like growth factor-I (IGF-I) is essential for cell growth, differentiation and postnatal development. A null mutation in igf-1 causes intrauterine growth retardation and perinatal lethality. The present study was designed to test the lower limit of igf-1 gene dosage that ensures survival and postnatal growth by using the Cre/loxP system. Mice with variable reductions in IGF-I levels were generated by crossing EIIa-cre transgenic mice and mice with loxP-flanked igf-1 locus (igf-1/flox). EIIa-cre mice express bacteriophage P1 Cre (causes recombination) recombinase under the adenovirus promoter EIIa, during early embryonic development before implantation, and cause genomic recombination of the igf-1/flox locus. Mice with the most extensive recombination die immediately after birth, while the survivors have significant growth retardation in proportion to the reduction in their igf-1 gene. Interestingly, this gene dosage effect on body weight was not very significant before weaning. However, when the young animals were weaned at 3 weeks, the igf-1 gene dosage was the only independent predictor of the weight gain between 3 and 6 weeks among the parameters tested. Although growth retarded, mice with Cre-induced partial igf-1 deficiency were fertile and gave birth to null mice. Thus Cre-induced genomic recombination using the EIIa promoter occurs during development and creates distinct phenotypes compared with the conventional null mutation. This variability allows for postnatal survival and will enable one to begin to explore the role of the endocrine vs. paracrine effects of IGF-I.
Characterization of the Thyroxine-Binding Site of Thyroxine-Binding Globulin by Site-Directed Mutagenesis
Authors: Buettner Christoph , Grasberger Helmut , Hermansdorfer Kristine , Chen Bingkun , Treske Bettina , Janssen Onno E. 
Published: January 2014

AbstractThe principal transport protein for T4 in human blood, thyroxine-binding globulin (TBG), binds T4 with an exceptionally high affinity (Ka = 1010m−1). Its homology to the superfamily of the serpins has recently been used in the design of chimeric proteins, providing experimental evidence that an eight-stranded β-barrel domain encompasses the ligand-binding site. We have now characterized the T4 binding site by site-directed mutagenesis. Sequence alignment of TBG from several species revealed a phylogenetically highly conserved stretch of amino acids comprising strands 2B and 3B of the β-barrel motif. Mutations within this region (Val228Glu, Cys234Trp, Thr235Trp, Thr235Gln, Lys253Ala, and Lys253Asp), designed to impose steric hindrance or restriction of its mobility, had no significant influence on T4 binding. However, binding affinity was 20-fold reduced by introduction of an N-linked glycosylation site at the turn between strands 2B and 3B (Leu246Thr) without compromising the proper folding of this mutant as assessed by immunological methods. In most other serpins, this glycosylation site is highly conserved and has been shown to be crucial for cortisol binding of corticosteroid-binding globulin, the only other member of the serpins with a transport function. The ligand-binding site could thus be located to a highly aromatic environment deep within theβ -barrel. The importance of the binding site’s aromatic character was investigated by exchanging phenylalanines with alanines. Indeed, these experiments revealed that substitution of Phe249 in the middle of strand 3B completely abolished T4 binding, while the substitution of several other phenylalanines had no effect.