bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of human myometrial Gαs messenger ribonucleic acid transcript during pregnancy and labour: involvement of alternative splicing pathways
Authors: Europe-Finner G N , Phaneuf S , Cartwright E , Mardon H J , Bernal A López 
Published: December 2004

ABSTRACT
We have shown previously that expression of 46 and 54 kDa human myometrial Gαs protein isoforms is increased during gestation and then subsequently decreased during labour. These proteins appear to be coded for by Gαs-Small (with a serine residue at position 72) and Gαs-Large (with a serine residue at position 87) mRNA splice variants respectively. In the study presented here we have used a Gαs cDNA template to generate [32P]cytidine cRNA ribo-probes for use in RNase protection assays, so as to measure total myometrial Gαs mRNA levels in relation to the pattern of expression of Gαs mRNA splice variants during pregnancy and labour. We report that total levels of human myometrial Gαs mRNA remain similar in non-pregnant and pregnant women but are substantially reduced during parturition. Our data also provide strong evidence that alternative splicing of Gαs precursor mRNA has a primary role in regulating expression of Gαs protein isoforms during pregnancy and labour. The inclusion of an additional serine codon in Gαs mRNAs during pregnancy involves a switch in alternative splicing pathways. We speculate that this switch may be due to a change in specificity of splicing factors that are modulated during pregnancy and labour.
A one-nucleotide difference in a cAMP and phorbol ester response element leads to differential regulation of the human chorionic somatomammotropin A and B gene transcription
Authors: Oury C , Alsat E , Jacquemin P , Evain-Brion D , Martial J A , Muller M 
Published: December 2004

ABSTRACT
Human chorionic somatomammotropin (hCS) is encoded by two highly related genes, hCS-A and hCS-B, located in the hGH/hCS gene locus. Both genes are expressed in the syncytiotrophoblast layer of the placenta and hCS release from trophoblast cells is known to be increased by cAMP and phorbol esters. However, it remains unclear whether this regulation acts at the level of hCS gene expression or secretion and whether both genes are affected. We examined the effects of cAMP and phorbol 12-myristate 13-acetate (PMA) on the transcription of the hCS-A and hCS-B genes. Transient expression experiments revealed a 7 bp cAMP- and PMA-responsive element (CRElhCS-A) spanning nucleotides −1102 to −1096 upstream of the hCS-A gene. In contrast, the homologous sequence upstream of hCS-B (CRElhCS-B), differing from CRElhCS-A by a single substitution, shows little or no response to cAMP. In band-shift assays, the CRElhCS-A oligonucleotide was shown to bind two factors related to CREBP and AP-1, whereas CRElhCS-B only competes for one of these complexes. Finally, Southwestern analysis revealed that the CRElhCS-A element binds two ubiquitous proteins of 100 kDa and 47 kDa respectively, whereas CRElhCS-B interacts only with the 47 kDa protein. Taken together, these results suggest that a 47 kDa protein binding to the CRElhCS-A and CRElhCS-B elements is involved in the PMA response of the hCS-A and hCS-B genes, and a 100 kDa protein plays a crucial role in cAMP regulation of the hCS-A gene.
Bovine thyrotropin receptor cDNA is characterized by full-length and truncated transcripts
Authors: Silversides D W , Houde A , Ethier J-F , Lussier J G 
Published: December 2004

ABSTRACT
The complete coding sequence for the bovine thyrotropin (TSH) receptor was derived using a modified PCR cloning strategy. The bovine thyrotropin receptor conforms to the pattern of receptor interacting with membrane-bound G-protein already established in other species for TSH and gonadotropins receptors. The cDNA for the bovine TSH receptor consists of an open reading frame 2289 nucleotides in length, corresponding to a protein of 763 amino acids (estimated molecular mass of 86·4 kDa) which includes a 20 amino acid putative leading signal peptide. The receptor consists of a large NH2-terminal extracellular membrane domain of 417 amino acids with 5 potential N-linked glycosylation sites, a transmembrane domain (265 amino acids) consisting of 7 putative membrane α-helix spanning segments, and an intracytoplasmic COOH-terminal domain (82 amino acids). The bovine TSH receptor is one amino acid less than the corresponding sequence in dog, human, rat and mouse. Cysteine residues (n=22) were conserved when compared with other TSH receptors. Three potential phosphorylation sites were found in the transmembrane domain and the COOH-terminal domain. As with other members of this receptor family, alternative splicing was observed. A transcribed but truncated TSH receptor of 1769 nucleotides was demonstrated, lacking half of the V segment of the transmembrane domain up to the COOH-terminal domain of the full length TSH receptor. Additionally, alternative transcriptional start sites were observed. Northern blot analysis using a probe (1170 bp) spanning part of the extracellular domain up to the first loop of the transmembrane domain showed specific expression in the bovine thyroid gland with major transcripts of 9·3 and 4·3 kb, and a minor transcript of 3·8 kb being detected.
Action of peripheral or intrathyroidal lymphocytes on autologous thyrocytes cultured in follicles in collagen gel
Authors: Massart C , Gibassier J , Raoul M L , Le Gall F , Lancien G , Genetet N , Denais A , Darcel F , Lucas C 
Published: December 2004

ABSTRACT
We have studied the action of peripheral blood lymphocytes (PBLs) and intrathyroidal lymphocytes (ITLs) on the biochemical and hormonal metabolism of autologous thyrocytes cultured in follicles in a collagen gel. The production of tumour necrosis factor α (TNF-α) in culture was also measured. Thyroid tissues and lymphocytes were obtained from ten patients with Graves' disease and from five control subjects. Lymphocyte-induced cytotoxicity was evaluated in autologous thyrocytes cultured in a collagen gel by several tests: neutral red uptake, lactate dehydrogenase activity and glutathione level. Hormonal metabolism was assessed by evaluating tri-iodothyronine (T3) and total cAMP production under TSH stimulation. TNF-α levels were measured in supernatants after 5 days of coculture. PBLs altered biochemical metabolism, T3 synthesis and cAMP production in autologous thyroid follicles. These inhibitions were greater than those obtained with ITLs. No difference was seen between cells obtained from patients with Graves' disease and those from normal subjects. TNF-α levels secreted by PBLs were higher than those secreted by ITLs. The concentrations of this cytokine decreased in coculture. Significant correlations were observed between the decrease in biochemical and hormonal parameters and TNF-α levels. Exogenous TNF-α and high doses of interferon γ inhibited follicle metabolism, especially hormone secretion.
In conclusion, thyrocytes cultured in follicles provide a more sensitive model than monolayer cultures for analysis of lymphocyte-induced interactions. Lymphocytes gradually inhibit the biochemical and hormonal metabolism of autologous thyroid follicles depending on the isolation method. These alterations may be particularly attributed to TNF-α secreted by lymphocytes. The cytokine-induced inhibition of thyroid hormonal function apparently involves the adenylate cyclase system.
Cloning, sequencing and in vitro functional expression of recombinant donkey follicle-stimulating hormone receptor: a new insight into the binding specificity of gonadotrophin receptors
Authors: Richard F , Martinat N , Remy J-J , Salesse R , Combarnous Y 
Published: December 2004

ABSTRACT
Among all mammalian FSH receptors (FSH-R; including donkey (dk) FSH-R), only horse (hs) FSH-R does not bind hsLH/chorionic gonadotrophin (CG). In order to delineate the structural origin of hsFSH-R specificity precisely, we have cloned dkFSH-R cDNA from donkey testis mRNA by RT-PCR. Transiently expressed dkFSH-R endowed COS-7 cells with both hsLH/CG- and FSH-binding activity, as well as FSH-induced cAMP production.
The deduced dkFSH-R amino acid sequence shares 96% identity with the hsFSH-R: notably, in the hormone-binding domain, the specificity of hsFSH-R may be ascribed to only four divergent amino acids: Thr 173, Asp 202, Asn 268 and Pro 322. Interestingly, hsAsn 268 could bear an additional N-glycosylation. According to receptor negative specificity, these amino acids could be implicated in preventing LH/CG binding to FSH-R.
The role of GH receptor tyrosine phosphorylation in Stat5 activation
Authors: Hansen J A , Hansen L H , Wang X , Kopchick J J , Gouilleux F , Groner B , Nielsen J H , Møldrup A , Galsgaard E D , Billestrup N 
Published: December 2004

ABSTRACT
Stimulation of GH receptors leads to rapid activation of Jak2 kinase and subsequent tyrosine phosphorylation of the GH receptor. Three specific tyrosines located in the C-terminal domain of the GH receptor have been identified as being involved in GH-stimulated transcription of the Spi 2·1 promoter. Mutated GH receptors lacking all but one of these three tyrosines are able to mediate a transcriptional response when transiently transfected into CHO cells together with a Spi 2·1 promoter/luciferase construct. Similarly, these GH receptors were found to be able to mediate activation of Stat5 DNA-binding activity, whereas the GH receptor mutant lacking all intracellular tyrosines was not. Synthetic tyrosine phosphorylated peptides corresponding to the GH receptor sequence around the three tyrosines inhibited Stat5 DNA-binding activity while their non-phosphorylated counterparts were ineffective. Tyrosine phosphorylated GST-GH receptor fusion proteins specifically bound to Stat5 in extracts from COS 7 cells transfected with Stat5 cDNA. This binding could be inhibited by tyrosine phosphorylated peptides derived from the GH receptor. This study thus demonstrated that specific GH receptor tyrosine residues, in their phosphorylated state, are involved in transcriptional signaling by directly interacting with Stat5.
Inappropriate expression of human transforming growth factor (TGF)-α in the uterus of transgenic mouse causes downregulation of TGF-β receptors and delays the blastocyst-attachment reaction
Authors: Das S K , Lim H , Wang J , Paria B C , BazDresch M , Dey S K 
Published: December 2004

ABSTRACT
In the mouse, the initiation of the attachment reaction between the blastocyst trophectoderm and luminal epithelium of the receptive uterus occurs in the evening (2200-2300 h) of day 4 of pregnancy (day 1=vaginal plug) and is followed by proliferation and differentiation of stromal cells into decidual cells at the sites of blastocyst attachment. This investigation demonstrates that an inappropriate expression of the human transforming growth factor α (hTGF-α) transgene in the uterus under the direction of a mouse metallothionein-I promoter downregulates uterine expression of TGF-β receptor subtypes and delays the initiation of implantation (attachment reaction) resulting in delayed parturition. This delay in the attachment reaction is accompanied by deferred uterine expression of amphiregulin. The results suggest that a coordinated 'cross-talk' between the signaling pathways executed by epidermal growth factor-like growth factors and TGF-βs is important for the normal implantation process.
Glucocorticoids enhance corticotropin receptor mRNA levels in ovine adrenocortical cells
Authors: Picard-Hagen N , Penhoat A , Hue D , Jaillard C , Durand P 
Published: December 2004

ABSTRACT
We have shown previously that chronic treatment with glucocorticoids enhances both ACTH-induced cAMP production and ACTH- or 8Br-cAMP-induced steroidogenesis of cultured ovine adrenocortical cells. This treatment has been shown to involve an increase in the number of ACTH receptors. The present study aimed to explore the mechanism of this effect of glucocorticoids on ACTH receptors. Ovine adrenocortical cells expressed one major ACTH receptor transcript of 3·6 kb and three minor ones of 4·2, 1·8 and 1·3 kb. Dexamethasone treatment of cultured cells increased the levels of all these transcripts in a time- and dose-dependent manner, with an EC50 of (1·5±0·6) × 10−8 m. The mean increase over control with 10−6 m dexamethasone was 144 ± 11% (n=14). This enhancing effect was specific for glucocorticosteroids. The antiglucocorticoid Ru38486 blocked the effect of dexamethasone. Testosterone did not modify, while high concentrations of 17β-estradiol decreased, ACTH receptor mRNA levels. Treatment of cells with aminoglutethimide (an inhibitor of steroidogenesis) resulted in a dose-dependent decrease in ACTH receptor mRNA levels, which was prevented by concomitant treatment with dexamethasone. Treatment with ACTH also increased ACTH receptor mRNA levels more than twofold. Addition of aminoglutethimide together with ACTH resulted in a smaller increase than that achieved with ACTH alone. Neither dexamethasone nor ACTH modified ACTH receptor mRNA half-lives. However, these two hormones enhanced the levels of both newly synthesized and total ACTH receptor mRNAs. These results indicate that the positive trophic effect of glucocorticoids on ovine adrenocortical cells involves an enhancement of the transcription rate of the ACTH receptor gene. In addition, they suggest that part of the trophic action of ACTH on ACTH receptors may be mediated by ACTH-induced steroidogenesis.
Investigation of the potential role of the germ cell complement in control of the expression of transferrin mRNA in the prepubertal and adult rat testis
Authors: Maguire S M , Millar M R , Sharpe R M , Gaughan J , Saunders P T K 
Published: December 2004

ABSTRACT
Iron is required for the normal development of germ cells during spermatogenesis. Because these cells have no direct access to systemic iron, there exists a shuttle system involving production and secretion of the iron-transporting protein transferrin by the Sertoli cells. Previous reports using cultures of immature Sertoli cells exposed to adult germ cells, or in vivo studies involving germ cell-depleted adult rat testes, concluded that production of transferrin by Sertoli cells is modulated by germ cell complement.
In the present study we have used in situ hybridisation with cRNA probes directed against the 5′ and 3′ ends of transferrin mRNA to examine the pattern of expression of transferrin in the immature and adult rat testis. Adult rats were treated with ethane dimethane sulphonate or methoxyacetic acid (MAA) to manipulate their testosterone levels or germ cell complement respectively. Initial findings obtained using the 3′ probe showed a decrease in transferrin mRNA associated with round spermatid depletion. However, these data were not confirmed by in situ hybridisation when the 5′ probe was used. The specificity of the probes was examined using Northern blotting and the 3′ probe was found to hybridise to the germ cell transcript for hemiferrin even under conditions of high stringency. Examination of immature and pubertal rat testes by in situ hybridisation using the 5′ transferrin-specific probe found that as early as 14 days of age the level of expression of transferrin mRNA was clearly different between tubules, and the mRNA appeared to be expressed in Leydig cells on and after day 31. In the adult rat testis, maximal expression of transferrin mRNA was found at stages VIII-XIV, calling into question the interpretation of the results of some previous studies showing expression of transferrin mRNA at all stages of the spermatogenic cycle. This stage-specific pattern of expression was not altered by acute germ cell depletion using MAA. However, Northern blot analysis showed a statistically significant increase in transferrin mRNA expression at 7 days after MAA treatment when pachytene spermatocytes were depleted from tubules at all stages of the spermatogenic cycle at which transferrin is normally expressed.
In conclusion, we found that transferrin mRNA expression was not modulated by round spermatids as has been reported previously but that meiotic germ cells may influence expression of transferrin at specific stages of the spermatogenic cycle.
Somatostatin does not inhibit prolactin synthesis in normal male rat pituitary cells but inhibits prolactin synthesis in estradiol-primed pituitary cells
Authors: Lee S C , Shin S H 
Published: December 2004

Abstract
The effects of somatostatin (SRIF) on prolactin (PRL) synthesis and release were examined in primary cultured pituitary cells derived from normal and estradiol (E2)-primed male rat pituitaries. The cells were continuously incubated in a pulse medium containing [3H]leucine with or without 10−6 mol/l SRIF for a period of 15, 30, 60, 180 or 360 min. Following incubation, the medium was recovered and the cells were fractionated into cytosolic and granular fractions. PRL was isolated by SDS-PAGE and newly synthesized PRL ([3H]PRL) was identified by coincident peaks of tritium activities and PRL contents. The specific activity (SA, c.p.m./ng), a ratio of [3H]PRL to total PRL, was determined for the granular, cytosolic and medium fractions.
In control and SRIF-treated groups of non-primed pituitary cells, SAs of all three fractions significantly increased during the 6-h incubation. Cytosolic and granular SAs showed similar profiles of increasing rate in comparison to control. Medium SAs showed a significantly higher value in the SRIF-treated group than in the control group only at 180 min. These observations indicate that, in the non-primed condition, PRL synthesis is not inhibited by SRIF. Medium SAs in the E2-primed group were significantly higher than SAs in the non-primed control cells during the initial 3 h of incubation, and cytosolic and granular SAs were significantly higher than those of the non-primed control during the 3- to 6-h incubation period. These observations demonstrate that E2 enhances PRL synthesis and secretion of newly synthesized PRL. SRIF treatment of E2-primed lactotrophs resulted in a significant decrease in SAs of all three fractions as compared with those of the E2-primed control. Our results indicate that in normal male rat pituitary cells SRIF does not inhibit PRL synthesis but effectively inhibits PRL synthesis in E-primed lactotrophs. This suggests that the inhibitory action of SRIF on PRL synthesis is estrogen dependent.
Journal of Endocrinology (1996) 148, 69–76
Inhibition of agonist-mediated calcium entry by calmodulin antagonists and by the Ca2+/calmodulin kinase II inhibitor KN-62. Studies with thyroid FRTL-5 cells
Authors: Törnquist K , Ekokoski E 
Published: December 2004

Abstract
Calmodulin and calmodulin-dependent mechanisms are probably important in regulating thyroid cell function. However, calmodulin antagonists may directly modify calcium fluxes in cells. In the present investigation the effects of several calmodulin inhibitors and of KN-62, a specific calcium/calmodulin kinase II inhibitor, on the ATP- and thapsigargin-evoked changes in intracellular free calcium ([Ca2+]i) were investigated in Fura-2 loaded thyroid FRTL-5 cells. All of the inhibitors tested attenuated agonist-evoked calcium entry. The inhibitor calmidazolium per se potently released sequestered calcium followed by enhanced calcium entry. Pretreatment of the cells with calmidazolium inhibited both the thapsigarginand the ATP-evoked calcium entry. Our results show that calmodulin antagonists are potent inhibitors of calcium entry in thyroid cells, possibly by directly inhibiting the calcium entry pathway. This inhibition may explain, in part, the results obtained with calmodulin inhibitors in previous studies.
Journal of Endocrinology (1996) 148, 131–138
Interleukin-1 effect on glycemia in the non-obese diabetic mouse at the pre-diabetic stage
Authors: Amrani A , Jafarian-Tehrani M , Mormède P , Durant S , Pleau J-M , Haour F , Dardenne M , Homo-Delarche F 
Published: December 2004

Abstract
Cytokines, particularly interleukin 1 (IL-1) and tumor necrosis factor, are known to induce hypoglycemia in normal rodents or different experimental models of type II diabetes. We investigated, at the pre-diabetic stage, the effect of short-term administration of murine recombinant interleukin-1α (mrIL-1α) on the levels of glucose, insulin and corticosterone in the non-obese diabetic (NOD) mouse, a spontaneous model of type I diabetes. Two-month-old, pre-diabetic NOD mice of both sexes were insensitive to mrIL-1α (12·5 and 50 μg/kg) 2 h after administration, the time at which the maximal decrease (around 50%) was observed in the C57BL/6 mouse strain. Kinetic studies however showed that mrIL-1α lowered glycemia in both sexes of NOD mice, but the effect was limited and delayed. In the NOD and C57BL/6 strains, mrIL-1α had no influence on insulin levels in females, but significantly increased them in males (P<0·0001). Castration of NOD males abrogated the stimulatory effect of mrIL-1α on insulin secretion. Corticosterone secretion was stimulated by mrIL-1α in both sexes of NOD and C57BL/6 mice, and this effect was faster and greater in NOD females than in C57BL/6 females. The incomplete hypoglycemic response to mrIL-1α in females may be attributed to the anti-insulin effect of glucocorticoids, an effect which can be demonstrated when mrIL-1α is administered to adrenalectomized animals or when mrIL-1α is administered together with the glucocorticoid antagonist RU38486. In NOD males, in contrast, glucocorticoids did not play a major role in the limited hypoglycemic response to mrIL-1α, since RU38486 and adrenalectomy were not able to unmask a hypoglycemic effect. Moreover, NOD mice of both sexes were less sensitive than C57BL/6 mice to the hypoglycemic effect of insulin (2·5 U/kg), which suggests some degree of insulin-resistance in NOD mice. With regard to the effect of IL-1 on NOD mouse glycemia, therefore, these results suggest that glucocorticoids and/or androgens, according to the animal's sex, may induce a state of insulin-resistance.
Journal of Endocrinology (1996) 148, 139–148
Thermic effect of food in hypothyroid rats
Authors: Iossa S , Lionetti L , Mollica M P , Barletta A , Liverini G 
Published: December 2004

Abstract
The regulatory and obligatory components of cephalic and gastrointestinal phases of the thermic effect of food (TEF) were measured in control and hypothyroid rats. A significant decrease (P<0·05) in regulatory and obligatory components of cephalic and gastrointestinal TEF, after either a control or energy-dense meal, was found in hypothyroid rats compared with control rats. Our findings indicate that hypothyroidism is associated with a decreased thermogenic response to food which contributes to the reduced energy expenditure of hypothyroid rats. Our results also suggest that tri-iodothyronine is involved in the regulation of postprandial thermogenesis directly as well as through its influence on β-adrenergic response and insulin release.
Journal of Endocrinology (1996) 148, 167–174