bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth hormone and prolactin affect oxytocin, vasopressin, progesterone and cyclic nucleotide secretion by bovine granulosa cells in vitro
Authors: Sirotkin A V , Nitray J 
Published: December 2008

Abstract
The effects of growth hormone (GH) and prolactin (PRL) (1, 10, 100, 1000 or 10 000 ng/ml medium) on oxytocin, vasopressin, progesterone, cAMP and cGMP release by cultured bovine granulosa cells were studied. It was found that GH significantly stimulated oxytocin, vasopressin and cAMP but suppressed progesterone secretion. PRL tended to have the same pattern of action on nonapeptide, cAMP and steroid release, but its effect was not as great, with only a high supraphysiological dose (10 000 ng/ml) producing a statistically significant effect. No significant influence of GH on cGMP output was observed. Physiological doses of PRL (1, 10, 100 or 1000 ng/ml) significantly inhibited cGMP production whilst a high dose (10 000 ng/ml) resulted in stimulation.
These observations suggested that GH may regulate ovarian oxytocin, vasopressin, progesterone and cAMP secretion. The effects of PRL on the release of these substances appeared to be non-specific, possibly resulting from its structural similarity to GH.
Journal of Endocrinology (1994) 143, 417–422
Angiotensin II (All)-binding sites in nuclei from rat liver: partial characterization of the mechanism of All accumulation in nuclei
Authors: Jiménez E , Vinson G P , Montiel M 
Published: December 2008

Abstract
Isoelectric focusing analysis showed a single angiotensin II (All)-receptor complex migrating to pI 6·8 in nuclear preparations, while in plasma membranes a charge heterogeneity of the All receptor subtype AT1 was observed. 125I-Labelled All binding sites were found in intact nuclei and were not detected in nuclear extracts. Neither disruption of cytoskeletal elements by colchicine nor prevention of endosome acidification by chloroquine had any effect on nuclear accumulation of AIL Nevertheless, the monovalent ionophore monensin inhibited nuclear accumulation of 125I-Labelled All. Our findings are consistent with the hypothesis that processing through the Golgi apparatus could be involved in the nuclear accumulation of AIL
Journal of Endocrinology (1994) 143, 449–453
Horse plasma corticotrophin-releasing hormone (CRH): characterisation and lack of a late gestational rise or a plasma CRH-binding protein
Authors: Ellis M J , Livesey J H , Donald R A 
Published: December 2008

Abstract
Immunoreactive corticotrophin-releasing hormone (irCRH) was present in methanolic extracts of equine peripheral blood and showed no elevation in maternal peripheral serum in late gestation (0·54 ±0·25 pmol/l; mean ± s.d.) compared with control horses (0·41 ± 015 pmol/l). The irCRH of methanolic extracts of pituitary venous plasma had a similar elution position following reverse-phase HPLC to synthetic human CRH(1–41) and to irCRH released from horse stalk-median eminence tissue incubated in vitro. Gel chromatographic studies showed no evidence for a plasma CRH-binding protein (CRHBP) analogous to that found in human plasma in either peripheral blood from normal or pregnant horses or in pituitary venous plasma sampled from a cannulated horse. CRH-binding activity was detectable in peripheral plasma from one horse, however the molecular size of this was indicative of a γ-globulin rather than the 37 kDa CRHBP.
These studies suggest that, unlike in the human, CRH does not rise to high values in late gestation nor circulate in a bound form in equine plasma.
Journal of Endocrinology (1994) 143, 455–460
Effects of insulin-like growth factor-I (IGF-I) and IGF-II on the growth of antler cells in vitro
Authors: Sadighi M , Haines S R , Skottner A , Harris A J , Suttie J M 
Published: December 2008

Abstract
The effects of insulin-like growth factors -I and -II (IGF-I and -II) on the growth of undifferentiated (fibroblast zone) cells from the growing tip of red deer velvet antlers and from cells 1·5 cm distal to the growing tip (cartilage zone) were investigated in primary cell culture. The addition of IGF-I or IGF-II to the medium of cultures preincubated in serum-free medium for 24 h increased the rate of [3H]thymidine uptake in a dose-dependent manner in both cell types, with maximal stimulation occurring when 1 nm–30 nm was added. The addition of IGF-II to the incubation medium containing IGF-I did not cause a further increase in [3H]thymidine uptake in either cell type over and above each growth factor alone, indicating that there were unlikely to be synergistic effects of IGF-II on the mitogenicity of IGF-I. Binding studies were carried out using 3 × 105 fibroblast zone cells and cartilage zone cells after they had been incubated in serum-free medium for 24 h. 125I-Labelled IGF-I (10−9 m) in a final volume of 200 μl was added to each culture and incubation carried out at 4 °C for a further hour. 125I-Labelled IGF-I bound specifically to both fibroblasts and cartilage zone cells; binding was displaced by both unlabelled IGF-I and by IGF-I antibody. These findings indicate that IGF-I and IGF-II are important mediators for antler growth in vitro and suggest that in view of correlations between IGF-I and antler growth, IGF is functionally significant in controlling velvet antler growth in vivo.
Journal of Endocrinology (1994) 143, 461–469
The effect of germ cell complement on the presence of oxytocin in the interstitial and seminiferous tubule fluid of the rat testis
Authors: Nicholson H D , Greenfield H M , Frayne J 
Published: December 2008

Abstract
In the rat testis oxytocin has been localized to the Leydig cells, and these cells have been shown to produce oxytocin in vitro. The present study was performed to determine whether oxytocin is present in the interstitial fluid (IF) and seminiferous tubule fluid (TF) of the rat and whether concentrations of the peptide vary within the two compartments following germ cell destruction.
In order to destroy germ cells adult male rats were anaesthetized and their scrotal regions placed in a water bath at 43 °C for 20 min. Control animals were subjected to anaesthesia alone. Groups of 6 animals were killed 3, 7 and 21 days after heat treatment and their testes removed for histological examination or fluid extraction. IF and TF were separated and the oxytocin content of the fluids measured by radioimmunoassay.
Immunoreactive oxytocin was detected in both the IF (100 ±11 pg/ml) and TF (27± 4 pg/ml) of control rats and this immunoreactivity co-eluted with the authentic peptide following HPLC. Three days after heat treatment IF levels of oxytocin were significantly reduced but TF levels of the peptide were significantly increased. These changes were associated with a lack of pachytene spermatocytes in the histological sections. Seven and 21 days after heat treatment the levels of oxytocin in the IF and TF were not significantly different from control levels. Similar changes in IF and TF oxytocin levels were seen in a second experiment when pachytene spermatocytes were removed using the testicular toxicant methoxyacetic acid.
To investigate whether oxytocin passes from the IF into the TF, 3H-oxytocin was infused into the testicular arteries of both control and heat-treated rats and the rats killed at regular intervals over the next 24 h. In both groups of animals <5% of the 3H-oxytocin passed from the IF into the TF.
These data suggest that the seminiferous tubule as well as the Leydig cells may secrete oxytocin and that this secretion may be influenced by the presence of germ cells, particularly pachytene spermatocytes.
Journal of Endocrinology (1994) 143, 471–478
An investigation of the ability of TSH and Graves' immunoglobulin G to increase intracellular calcium in human thyroid cells, rat FRTL-5 thyroid cells and eukaryotic cells transfected with the human TSH receptor
Authors: MacNeil S , Munro D S , Metcalfe R , Cotterell S , Ruban L , Davies R , Weetman A P 
Published: December 2008

Abstract
The purpose of this study was to determine if immunoglobulin G preparations (IgGs) from patients with Graves' disease can increase intracellular calcium in thyroid cells, as has been reported for TSH. Both TSH and Graves' IgGs (prepared by protein G affinity chromatography) increased calcium in a range of thyroid cells; however, the response seen, using Fura-2-loaded coverslips of cell monolayers, varied considerably. Chinese hamster ovary (CHO/JPO9) cells transfected with a high number of human TSH receptors showed the greatest response: TSH (10 mU/ml) increased calcium in 46% of experiments and 18 out of 25 (72%) Graves' IgGs increased calcium at 0·1 mg/ml (significantly greater, P<0·001, than for control IgGs where cells responded to 2 out of 13 preparations). Rat FRTL-5 cells only responded to TSH in 22% of experiments and to 2 out of 8 (25%) of Graves' IgGs. Similarly, human thyroid cells responded to TSH in 22% of experiments and to 2 out of 9 (22%) of Graves' IgGs. (When studying cyclic AMP responses in JPO9 cells, much higher concentrations of Graves' IgGs were required (1–3 mg/ml).) However, higher concentrations (03 mg/ml) of both Graves' IgGs, and to a lesser extent of control IgGs, were capable of increasing calcium in cells both with and without TSH receptors (control CHO cells and normal human dermal fibroblasts). We conclude that relatively low concentrations of patient IgGs can be distinguished from control IgGs in JPO9 cells on the basis of their ability to increase calcium, but that additionally all IgG preparations possibly contain another factor which can increase calcium in a range of cells independent of the presence of the TSH receptor.
Journal of Endocrinology (1994) 143, 527–540
Binding of thyroid hormone to the goat testicular Leydig cell induces the generation of a proteinaceous factor which stimulates androgen release
Authors: Jana N R , Bhattacharya S 
Published: December 2008

Abstract
Leydig cells isolated from goat testis were sonicated and pure nuclear preparations obtained for 125I-3,5,3′-triiodothyronine (T3)-binding assay. Under optimum assay conditions of pH 7·2 at 37 °C and 90 min of incubation, binding of 125I-T3 to Leydig cell nuclei reached saturation at 1·2 nmol/l concentration. A Scatchard analysis of T3 binding exhibited a Kd of 0·535 × 10−9 mol/l and a maximum binding capacity of 1·25 pmol/mg DNA. Competitive inhibition studies showed T3 binding to be analogue specific. The physiological relevance of T3 binding to goat Leydig cell was examined by adding increasing concentrations of T3 to the Leydig cell incubation (1×10 cells/incubation). T3 (10, 25 and 50 ng/ml or 4, 10 and 20 ng/incubation) resulted a dose dependent increase in androgen release and in all cases stimulation of androgen release was statistically significant (P<0·01) compared with control. Stimulation of Leydig cell androgen release by T3 was significantly inhibited by actinomycin-D (P<0·01) and cycloheximide (P<0·01). T3 had additive stimulatory effects on LH-augmented androgen release from Leydig cells. T3 (50 ng/ml or 20 ng/incubation) effected a more than twofold increase in Leydig cell protein synthesis compared with control and both actinomycin-D and cycloheximide (50 μg/ml) inhibited it completely. The data indicated that the stimulatory effect of T3 on androgen release is mediated via T3-induced protein(s). Sub-cellular fractions obtained from T3-treated Leydig cells showed an increase in protein synthesis in mitochondrial and soluble supernatant fractions (100 k sup) and it was only 100 k sup which stimulated androgen release from Leydig cells in separate incubations. Treatment of 100 k sup with trypsin or heat abolished its stimulatory effect. Incubation of Leydig cells with T3 for different times showed an increase in protein synthesis prior to the stimulation of androgen release. The results therefore indicated that T3 binding to Leydig cells induced the generation of a proteinaceous factor(s) which in turn stimulated androgen release.
Journal of Endocrinology (1994) 143, 549–556
The effect of oleic acid on the secretion of thyrotrophin and growth hormone by cultured rat anterior pituitary cells
Authors: Kennedy J A , Nicolson R , Wellby M L 
Published: December 2008

Abstract
Elevation of non-esterified fatty acids (NEFA) in vivo is associated with abnormal control of TSH. To determine whether TSH secretion is directly inhibited by NEFA, as has been reported for GH, cultured rat anterior pituitary cells were exposed for 20 h to oleic acid in medium containing 77 × 10−5 mol/l bovine serum albumin (BSA). In a molar ratio with albumin of 1·2 (total oleic acid 9× 10 mol/l), or greater, oleic acid inhibited basal GH secretion (maximum inhibition to 40% of control) while basal TSH was less affected, a ratio of 3 (2·3 × 10−4 mol/l oleic acid) or greater causing a smaller degree of inhibition (maximum inhibition to 80% of control). In the presence of 10−9 mol/l growth hormone-releasing hormone or 108 mol/l TRH, inhibition was achieved at a ratio of 12 (9 × 10−4 mol/l oleic acid) or greater. Basal TSH was less sensitive to inhibition by thyroxine (T4) in the presence of oleic acid/albumin at a ratio of 6 or greater, and inhibition by oleic acid was less than additive with T4 at a ratio of 6 or greater. Responses to tri-iodothyronine (T3) were unaffected at a ratio of 6 (4·6 × 10−4 mol/l oleic acid), but a ratio of 12 inhibited the effects of both T3 and T4 on TSH. Oleic acid had less effect in the presence of TRH, a ratio of 12 causing a small increase in the threshold concentration of T3 and T4 for TSH inhibition. Further studies are required to determine the mechanism by which oleic acid inhibits the response of basal TSH to T4 as well as the reason for a reduced effect of oleic acid in the presence of TRH. In some critically ill patients, total serum NEFA/albumin ratios from 1·5 to 6 have been reported, indicating that the direct inhibitory effects on TSH observed in vitro occur at free NEFA concentrations achieved in vivo. However, the direct inhibitory effect on TSH may be offset to some extent by reduced responsiveness to T4 at higher oleic acid concentrations. Hence other sites of action of NEFA in vivo may also be important in limiting TSH secretion. Further studies should examine the hypothalamic hormones like TRH and somatostatin, which control the thyrotrophs, as potential sites of action of NEFA.
Journal of Endocrinology (1994) 143, 557–564
Opioid peptides and testicular activity in the lizard Podarcis s. sicula Raf
Authors: Ciarcia G , Facchinetti F , Vallarino M , Pestarino M , Paolucci M , Cardone A , Fasano S , Pierantoni R , Genazzani A R 
Published: December 2008

Abstract
In mammals endorphinergic systems have been shown to modulate reproductive processes and β-endorphin (β-EP) has been found to influence sexual functions, acting at the hypothalamus-pituitary-gonadal axis level. Using immunocytochemical and in vitro studies, evidence for a diffuse pro-opiomelanocortin-related opioid system in the lizard Podarcis s. sicula was produced. In the testis, β-EP immunoreactivity showed seasonal variation, being most pronounced in the interstitial cells of sexually quiescent lizards (December). Reverse-phase high-performance liquid chromatography, coupled with radioimmunoassay and immunocytochemistry, showed that β-EP and acetyl β-EP increased during December, while their concentrations were low during April, when the highest testicular activity occurred.
Using in vivo studies, it was found that naltrexone treatment, blocking pituitary opioid receptor, increased androgen levels in the plasma and in the testis. It was also found with in vitro studies that the endogenous opioid system inhibits gonadotrophin release and therefore androgen production by the testis.
The data reported here provide evidence for the physiological role played by opioid peptides at the pituitary level to regulate the seasonal reproductive activity of the lizard Podarcis s. sicula.
Journal of Endocrinology (1994) 143, 565–571
Effects of basic fibroblastic growth factor on the function and proliferation of human clinically non-functional pituitary adenomas which secreted glycoprotein hormones in vitro
Authors: Atkin S L , Jeffreys R V , Foy P M , Hipkin L , Radcliffe J , White M C 
Published: December 2008

Abstract
The effects of human recombinant basic fibroblastic growth factor (bFGF) on the secretion, viability, proliferation, attachment and morphology of ten dispersed human clinically non-functional (NF) adenomas were examined in vitro. Four clinically NF adenomas secreting FSH and/or LH in vitro were unaffected by 10 nm bFGF over a 4-h period. Over 4 days 10 nm bFGF stimulated LH secretion (66% and 72%, P<0·01) from two out of seven clinically NF adenomas secreting LH, whilst FSH (three tumours) and α-subunit secretion (three tumours) were unaffected. One adenoma co-secreting LH and α-subunit and one secreting LH alone were studied over 21 days; LH secretion fell progressively, but the decline was significantly less (P<0·05) with bFGF (10 nm) treatment after 14 and 21 days in both adenomas, whilst the fall in α-subunit secretion was unaffected by bFGF treatment. A 24-h GnRH test performed at the start and end of the 21-day period in one of these tumours showed an increase in both basal and stimulated LH secretion in the bFGF-treated group over control (124%, P<0·001). There was no effect of bFGF (10 nm) on viability, S-phase proliferation, attachment or morphology of adenoma cells over a 4-day period. These results suggest that bFGF has a role in tumorous LH secretion from these adenomas, but is not mitogenic (at least over 4 days) and is without effect on other parameters of in vitro differentiated function.
Journal of Endocrinology (1995) 144, 173–178
In vivo responsiveness of thyroid glands to TSH in normal and novel 'growth-retarded' mice: transient elevation in normal mice and impairment in 'growth-retarded' mice
Authors: Tomita K , Yoshida T , Morita J , Atsumi S , Totsuka T 
Published: December 2008

Abstract
The in vivo responsiveness of thyroid glands to TSH at various ages in novel 'growth-retarded' (grt/grt) mice derived from Snell's dwarf (DW/J) mice and in their normal counterparts were analysed by determining serum T4 concentrations before and after the administration of exogenous TSH. The serum T4 concentration in normal mice increased in response to TSH at 2, 4 and 12 weeks of age but not at 1 week of age. A transient augmentation of such thyroidal responsiveness to TSH was apparent in normal mice at 2 weeks of age, when the serum T4 level exhibits a peak and the pubertal growth of mice starts. In contrast to normal mice, at any age examined from 2 to 12 weeks after birth, exogenous TSH did not influence serum T4 concentrations in the grt/grt mice at all. On the other hand, serum TSH concentrations in young grt/grt mice were highly elevated compared with those in normal mice and they were normalized by a 2–3 week's treatment with T3. Morphological studies demonstrated degenerated thyroid glands in the grt/grt mice. These results suggest that the severe hypothyroidism and consequent growth retardation in growth-retarded mice are due to impairment of the thyroid glands of the mutant mice in producing and/or secreting thyroid hormones in response to TSH.
Journal of Endocrinology (1995) 144, 209–214
Changes in IGF-I and -II expression and secretion during the proliferation and differentiation of normal rat osteoblasts
Authors: Birnbaum R S , Bowsher R R , Wiren K M 
Published: December 2008

Abstract
IGF-I and -II have potent effects on proliferation and differentiation of osteoblasts in vitro. These cells secrete both IGFs and expression of these peptides is regulated by several of the hormones and growth factors that promote bone resorption and/or formation. However, the physiological role(s) of IGFs in the remodelling process of adult bone is still unclear. Some confusion may arise from results influenced, in part, by differences in the state of osteoblast development of in vitro cultures. Several laboratories have demonstrated that murine osteoblast cultures progress from proliferating preosteoblasts, to mature differentiated osteoblasts that form an extracellular matrix, to cultures that form a mineralized matrix. We have recently documented changes in IGF-binding protein expression and secretion in these cultures. To complement and extend this work, we have examined IGF-I expression and secretion and IGF-II expression during in vitro osteoblast development.
Steady-state mRNA levels of both IGF-I and -II increased from the earliest time examined, day 5 in culture, to a maximum at day 11 and, thereafter, declined. IGF-I secreted into the medium also changed in a biphasic manner, but IGF-II could not be quantitated due to the sensitivity of our assay. Secretion of IGF-I was lowest between days 8 and 14. IGF-I secretion on day 5 was significantly greater than day 8. Similarly, IGF-I secretion from day 17 to 26 was also greater than observed for days 8 to 14. If differentiation of the cells was inhibited, this late rise in IGF-I secretion was abolished. We conclude that IGF-I is an autocrine mitogen of the proliferating preosteoblasts. Further, we also suggest that the rise in IGF-I secretion, late in osteoblast development, may lead to sequestration of this mitogen in the extracellular matrix for release during a subsequent remodelling cycle.
Journal of Endocrinology (1995) 144, 251–259
Inhibin forms in human plasma
Authors: Robertson D M , Sullivan J , Watson M , Cahir N 
Published: December 2008

Abstract
In order to identify the molecular weight forms of bioactive and immunoactive inhibin in human plasma, plasma/serum was sequentially fractionated by immunoaffinity chromatography (using immobilised inhibin α subunit antiserum), reversed phase HPLC and preparative SDS-PAGE. The electroeluted gel fractions were assayed for inhibin in vitro bioactivity and immunoactivity, the latter by RIA. Initial experiments examined human follicular fluid as an inhibin-rich source. Bioactive and immunoactive fractions of 30, 35, 53, 65 and ∼120 kDa were identified in addition to bio-inactive, immunoactive fractions of 26 kDa and 32 kDa. These molecular weights correspond to those of known inhibin forms and are attributed to differing degrees of glycosylation of the inhibin α subunit and variable processing of the α and β inhibin subunits.
Fractionation of male plasma pools revealed the presence of higher molecular weight immunoactive forms (55–120 kDa) as well as 28–31 kDa forms although the molecular weight distribution of activity between pools varied. To assess if the molecular weight pattern was modified by storage and/or subsequent fractionation, protease inhibitors were added initially to plasma and fractionated as above. The molecular weight distribution of immunoactivity was largely unaffected by the treatment, indicating that minimal processing had occurred. Postmenopausal serum itself showed low to undetectable activity. The addition of recombinant human 31 kDa inhibin to postmenopausal serum resulted in a molecular weight profile of inhibin immunoactivity consistent with the presence of 31 kDa inhibin. Fractionation of a serum pool from women undergoing gonadotrophin stimulation, in which inhibin levels were elevated, showed a range of bioactive and immunoactive inhibin forms over the 30–120 kDa range. A good correspondence between activities was observed.
It is concluded that: 1. inhibin exists in plasma/serum as a range (28–120 kDa) of molecular weight forms. 2. In female serum, the majority of inhibin isoforms appear to be bioactive. 3. This fractionation procedure provides a basis for investigating the forms of inhibin in plasma and provides a means of assessing the specificity of new assay methods.
Journal of Endocrinology (1995) 144, 261–269