bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of noradrenaline-induced inositol polyphosphate formation by glucocorticoids in rat vascular smooth muscle cells
Authors: Liu J. , Haigh R. M. , Jones C. T. 
Published: December 2008

ABSTRACT
Glucocorticoids are known to regulate the contractility of vascular smooth muscle by increasing its response to noradrenaline. The molecular mechanisms for achieving this remain unclear. Recent results in our laboratory have demonstrated that glucocorticoids affect both α1-adrenoceptor number and coupling to G proteins. Whether this leads to an increase in second-messenger production has to be established. The present experiments, therefore, report the effects of dexamethasone on inositol polyphosphate production in vascular smooth muscle cells in culture. Noradrenaline induced the release of inositol polyphosphates from prelabelled [3H]inositol phosphoinositides in the membrane in a dose-dependent manner. The concentration of noradrenaline which caused half-maximal response was 1·26 μmol/l. Prazosin inhibited noradrenaline-induced inositol monophosphate formation to 10·26 ± 3·67% (mean ± s.e.m.; P < 0·01, n = 5) of control value whereas yohimbine reduced it to only 61·74 ± 11·82% (P < 0·05, n = 5), suggesting an action primarily through α1-adrenergic receptors. Dexamethasone (100 nmol/l, 48 h) enhanced noradrenaline-induced inositol monophosphate, bisphosphate and trisphosphate formation up to twofold (P < 0·001, n = 5). The enhancement of the response occurred despite the fact that dexamethasone reduced [3H]inositol prelabelling of membrane phosphoinositides by 49·5 ± 9·9% (P < 0·05, n = 3). The present results suggest that the potential action of glucocorticoids on vascular smooth muscle contractility is, at least in part, through controlling α1-adrenoceptor-mediated second-messenger production.
Journal of Endocrinology (1992) 133, 405–411
Prostaglandin F2α- and phorbol 12-myristate-13-acetate-stimulated progesterone production by cultured human luteal cells in the mid-luteal phase: prostaglandin F2α increases cytosolic Ca2+ and inositol phosphates
Authors: Endo T. , Watanabe H. , Yamamoto H. , Tanaka S. , Hashimoto M. 
Published: December 2008

ABSTRACT
While prostaglandin F2α (PGF2α) has been thought to be a natural luteolysin in non-primates, a luteolytic effect in the human corpus luteum is less evident. We therefore investigated the action of PGF2α on monolayer cultures of human luteal cells obtained from mid-luteal phase corpora lutea.
PGF2α increased basal and human chorionic gonadotrophin (hCG)-stimulated progesterone production by human cultured luteal cells. A potent tumour-promoting phorbol ester, phorbol 12-myristate-13-acetate (PMA), also stimulated progesterone production by cultured human luteal cells.
Although human luteal cells were incubated for 24 h with PMA, hCG was still able to stimulate the production of progesterone by PMA-pretreated cells. However, PMA pretreatment blocked the ability of PGF2α to stimulate progesterone production. It is possible that the luteotrophic effect of PGF2α may be mediated, in part, by the activation of protein kinase C.
Addition of PGF2α to suspensions of human luteal cells preincubated with myo-[2-3H]inositol promoted an increase in labelled inositol phosphates. PGF2α also rapidly increased intracellular free Ca2+ in human luteal cells loaded with the fluorescent Ca2+ probe, fura-2.
We conclude that PGF2α and PMA stimulate progesterone production and that PGF2α increases the intracellular free calcium and inositol phosphates of human cultured luteal cells in the mid-luteal phase.
Journal of Endocrinology (1992) 133, 451–458
Localization of androgen receptors in human skin by immunohistochemistry: implications for the hormonal regulation of hair growth, sebaceous glands and sweat glands
Authors: Choudhry R. , Hodgins M. B. , Van der Kwast T. H. , Brinkmann A. O. , Boersma W. J. A. 
Published: December 2008

ABSTRACT
A mouse monoclonal antibody against the N-terminal region of human androgen receptor (AR) was used to identify receptors by immunoperoxidase staining in frozen serial sections of skin from scalp, face, limb and genitalia of men and women aged 30–80 years. AR staining was restricted to cell nuclei.
In sebaceous glands, AR were identified in basal and differentiating sebocytes. The percentage of receptor-positive basal sebocyte nuclei in the temple/forehead region was greater in males (65%) than in females (29%).
AR staining was restricted to the cells of dermal papillae in anagen and telogen hair follicles. The percentage of dermal papillae containing AR was greater in males (58%) than in females (20%). The number of positively stained dermal papillae was lowest in female scalp skin. In 163 hair follicles sectioned, AR were absent from germinative matrix, outer root sheath (including the bulge region), inner root sheath, hair shaft and hair bulb, and from the capillaries present in some large dermal papillae.
AR were present in pilosebaceous duct keratinocytes, suggesting that androgens may influence pilosebaceous duct keratinization. AR were also identified in interfollicular epidermal keratinocytes and dermal fibroblasts although, in both cell types, intensity and frequency of staining were greatest in genital skin. AR were identified in luminal epithelial cells of apocrine glands in genital skin and in certain cells of the secretory coils of eccrine sweat glands in all body sites.
This study indicates that androgens regulate sebaceous gland and hair growth by acting upon two different types of target cells, the epithelial sebocytes of sebaceous glands and the mesenchymal cells of the hair follicle dermal papilla. AR staining in either cell type was not influenced by age in adults. The distribution of AR in human skin is consistent with the diverse effects of androgens on the structure and function of skin and its appendages.
Journal of Endocrinology (1992) 133, 467–475
OESTROGEN AND PROGESTOGEN SYNERGISTICALLY STIMULATE HUMAN AND RAT OSTEOBLAST PROLIFERATION
Authors: Slootweg M.C. , Ederveen A.G.H. , Schot L.P.C. , Schoonen W.G.E.J. , Kloosterboer H.J. 
Published: December 2008

ABSTRACT
Oestrogens play an important role in bone metabolism; they preserve bone mass after the menopause. Their action in bone has recently been shown to be, partly, a direct one, as oestrogen receptors and their effects have been demonstrated in bone cells. The role of progestogens in bone metabolism is less clear. In this study it has been shown that 17β-oestradiol exerts only a small, although not significant, stimulatory action with regard to SaOS-2 human osteosarcoma cell proliferation. A pure progestogen (Org 2058) has no effect when added alone. In combination with 17β-oestradiol, however, it has a highly synergistic action on SaOS-2 cell proliferation. The same effect was observed in primary rat osteoblasts, showing that this synergism is a general phenomenon in osteoblastic cells. High numbers of oestrogen and progestogen receptors have been demonstrated in SaOS-2 cells, indicating that the effects of these steroids are mediated via the normal route of steroid receptors. These data provide a cellular basis for the clinically recognized positive effect of oestrogen/progestogen combinations on bone formation.
LONG TERM EFFECTS OF THYROID STIMULATING HORMONE AND INSULIN ON INTRACELLULAR pH IN FRTL-5 CELLS
Authors: Wood A.M. , Bidey S.P. , Soden J. , Robertson W.R. 
Published: December 2008

ABSTRACT
We have studied the chronic effects of TSH (100μU/ml) and insulin (10μg/ml) on intracellular pH (pHi) in FRTL-5 cells using the pH sensitive probe 2′7-bis (2-carboxyethyl-5′-6′) carboxyfluorescein. FRTL-5 cells were cultured on Petri dishes either in the presence of 4H, ie. Coons F-12 containing cortisol (10nM), transferrin (0.5μg/ml), glycyl-histidyl lysine acetate (10ng/ml) and somatostatin (10μg/ml), or with 4H+insulin (5H), 4H+TSH, or 4H+TSH+insulin (6H). pHi was measured in small groups of cells by microspectrofluorimetry both in the presence and absence of bicarbonate ions after cells had been deprived of serum for at least a day. In
Effect of active immunization of heifers against inhibin on plasma FSH concentrations, ovarian follicular development and ovulation rate
Authors: Glencross R. G. , Bleach E. C. L. , McLeod B. J. , Beard A. J. , Knight P. G. 
Published: December 2008

ABSTRACT
To study the effects of immunoneutralization of endogenous inhibin on gonadotrophin secretion and ovarian function, prepubertal heifers (n = 6) were actively immunized against a synthetic peptide replica of the N-terminal sequence of bovine inhibin α subunit bIα(1–29)Tyr30) coupled to ovalbumin. In contrast to ovalbumin-immunized controls (n=6), bIα(1–29)Tyr30-immunized heifers had detectable inhibin antibody titres (% binding to 125I-labelled bovine inhibin at 1:2000 dilution of plasma) of 17 ± 3% (s.e.m.) at puberty, rising to 31 ± 5% by the end of the study period 7 months later. Neither age (immunized: 295 ± 8 days; controls: 300 ± 5 days) nor body weight (immunized: 254 ± 13 kg; controls 251 ± 9 kg) at onset of puberty differed between groups. Although the difference did not reach statistical significance, mean plasma FSH concentrations recorded in inhibin-immunized heifers remained 35–40% higher than in controls throughout the 12-week period leading up to puberty (P = 0·14) and during nine successive oestrous cycles studied after puberty (P=0·10). Plasma LH concentrations did not differ between groups at any time during the study. Inhibin immunization had no effect on oestrous cycle length (immunized: 19·8±0·5 days; controls: 19·9±0·5 days). However, in comparison with controls, inhibinimmunized heifers had more medium sized (≥0·5 to <1 cm diameter) follicles during both the preovulatory (95%, P<0·001) and post-ovulatory (110%, P < 0·05 waves of follicular growth and more large (>1 cm diameter) follicles during the preovulatory wave (49%, P<0·05). In addition, the number of corpora lutea observed during the post-ovulatory phase of each cycle was significantly greater in the inhibin-immunized group (43%, P<0·01), as was the recorded incidence of cycles with multiple ovulations (19/56 in the inhibin-immunized group compared with 0/54 in controls; P<0·001). All six inhibinimmunized heifers had at least one cycle with multiple ovulation whereas none of the control heifers did so.
These results support the conclusion that immunoneutralization of endogenous inhibin using a synthetic peptide-based vaccine can enhance ovarian follicular development and ovulation rate in heifers. Whether this ovarian response is dependent upon the expected increase in secretion of FSH remains to be established.
Journal of Endocrinology (1992) 134, 11–18
The supraoptic nucleus in the pig hypothalamus: postnatal development and the effect of gonadal steroids
Authors: Van Eerdenburg F. J. C. M. , Lugard-Kok C. M. J. E. , Swaab D. F. 
Published: December 2008

ABSTRACT
Postnatal development of the supraoptic nucleus (SON) in the pig hypothalamus was studied morphometrically. The volume of the SON increased from 6·2±0·45 (s.e.m.) mm3 at 7 weeks postnatally to 18·5 ± 1·35 mm3 at 2·5 years of age. A sex difference was found at the development point when the SON volume increased, with earlier SON enlargement in males. This sex difference was 30% at 30 weeks and 50% at 1 year of age. At 2·5 years of age no difference in volume was apparent between the sexes. The number of SON neurones was similar for all age groups concerned (43 500 ± 1475), except for the 2·5year-old females where 40% more were found (55 500 ± 3285). No significant difference was found in neurone number between gonadectomized and sham-operated animals, but the operation caused a 30% reduction in the number of neurones and SON volume. Testosterone supplementation following gonadectomy, during the first 4 weeks postnatally, resulted in sexual dimorphism, the males having more SON neurones than the females. The volume showed only a trend in the same direction. Testosterone supplementation at other ages did not result in any difference when compared with controls.
The results of this study show that the postnatal development of the SON of the pig is sexually dimorphic, and that it continues after puberty in females. In contrast to the vasopressin- and oxytocincontaining nucleus, the development of the SON was not influenced by gonadectomy and only slightly by gonadal steroids.
Journal of Endocrinology (1992) 134, 19–25
Concanavalin-A-bound and -unbound prolactin in normal and hyperprolactinaemic rats
Authors: Champier J. , Claustrat B. , Harthe C. , Chevallier P. , Trouillas J. 
Published: December 2008

ABSTRACT
Concanavalin-A (Con-A)-bound and -unbound forms of prolactin were studied in female Wistar–Furth rats, both normal and with hyperprolactinaemia induced by treatment with oestrogen or a prolactinoma graft. In normal rats, Con-A-bound prolactin was the major circulating form (more than 50%) and a minor pituitary component (less than 10%), essentially as 25 kDa prolactin. In oestrogen-treated rats, plasma prolactin levels were 100-fold higher and pituitary weight was fivefold higher than in the controls, but total pituitary prolactin content was unmodified. Under oestrogen, Con-A-bound prolactin represented about one-third of the total hormone levels in the plasma and less than 10% in the pituitary. In the pituitary, bound prolactin was found essentially as 25 kDa and unbound prolactin as 22, 30 and 40–45 kDa. A similar increase in plasma prolactin levels was induced 6 months after the graft of a prolactinoma. Pituitary weights and total pituitary prolactin contents were slightly decreased. Plasma and pituitary Con-A-bound prolactin levels were similar to those observed in oestrogen-treated rats. On the other hand, unbound prolactin was only present as a 22 kDa monomer. In the tumour, Con-A-bound prolactin (essentially as 25 kDa prolactin) represented one-third of the total hormone level and unbound prolactin was composed of the 22 and 45 kDa forms, this latter form being partially transformed into 22 kDa by heating.
As Con-A-bound prolactin was previously characterized as glycosylated prolactin, these data suggest that glycosylated prolactin is present in the plasma of the normal rat as a major circulating form, unglycosylated 40–45 kDa is only present when the rate of the prolactin synthesis is high (in the pituitary of oestrogen-treated rats and in the tumour of grafted rats); this result supporting the hypothesis of a precursor product relationship between dimeric and monomeric prolactin. The manners in which prolactin is synthetized are not comparable in normal and tumour cells, percentages of glycosylated prolactin being different in normal pituitary and prolactinoma.
Journal of Endocrinology (1992) 134, 27–32
Short-term changes in the 3,5,3′-tri-iodothyronine nuclear receptor-binding capacity of porcine skeletal muscle following food intake
Authors: Morovat A. , Dauncey M. J. 
Published: December 2008

ABSTRACT
The time-course of changes in the nuclear 3,5,3′-tri-iodothyronine (T3) receptor-binding capacity (Bmax) of longissimus dorsi muscle has been investigated in cold-acclimated young pigs after a single large meal. Measurement of Bmax values 4, 8, 12 and 24 h after feeding indicated a decline in receptor numbers after food intake with the lowest values occurring at 8 h. The receptor numbers then increased significantly, with the values at 12 h being more than 50% higher than those obtained at 8 h. The Bmax values reached their highest level 24 h after feeding. No significant changes in the dissociation constant were observed. Possible reasons for the changes in T3 receptor numbers are discussed and it is suggested that the increase in T3 receptor numbers 12–24 h after feeding may play a role in enhancing the thermogenic capacity of the tissues in response to food.
Journal of Endocrinology (1992) 134, 67–72
Discordant secretion of relaxin by individual porcine large luteal cells: quantitative analysis by a reverse haemolytic plaque assay
Authors: Taylor M. J. , Clark C. L. 
Published: December 2008

ABSTRACT
Individual large luteal cells (LLC) derived from pregnant swine differ conspicuously in their ability to secrete the peptide hormone relaxin under basal and stimulated conditions – the phenomenon of functional heterogeneity. The purpose of this study was to quantitate knowledge of this phenomenon through use of a reverse haemolytic plaque assay, a technique that utilizes antibody-directed, complement-mediated erythrocyte lysis to detect hormone secretion by single LLCs in culture.
Measurement of individual plaque areas (an index of the amount of relaxin secreted) demonstrated an approximate 100-fold range in the amount of relaxin secreted by a single cell under basal conditions. This range was doubled by exposure to the phorbol ester, 4β-phorbol 12β-myristate 13α-acetate (PMA; 50 nmol/l). Under basal conditions, 50 and 80% of the total amount of relaxin was secreted by approximately 10 and 30% of all LLCs respectively. The size of these fractions was not influenced by the time of incubation (1–8 h), or by the presence of either of two non-specific stimulatory relaxin secretagogues, PMA (50 nmol/l) or arachidonic acid (1 μmol/l). The unimodal frequency distribution of plaque areas (under basal or stimulated conditions) suggests that relaxin-secreting LLCs comprise a discrete functional population of secretory cells, at least under these experimental conditions.
We conclude that a remarkably small fraction of LLCs secretes the majority of relaxin, and that the size of this fraction was not influenced by time or secretagogues.
Journal of Endocrinology (1992) 134, 77–83
Hormone-induced resistance of rat Leydig cells to the cytotoxic effects of ethane-1,2-dimethane sulphonate
Authors: Teerds K. J. , de Rooij D. G. , Wensing C. J. G. , Rommerts F. F. G. 
Published: December 2008

ABSTRACT
Several studies have shown that the cytotoxic agent ethane-1,2-dimethane sulphonate (EDS) specifically destroys Leydig cells in the adult rat testis. It has also been reported that when rats are pretreated with human chorionic gonadotrophin (hCG), administration of EDS does not result in the complete destruction of the Leydig cell population. It has been suggested that hCG pretreatment 'protects' Leydig cells against the cytotoxic action of EDS. In the present study the underlying principles for this resistance to the cytotoxic effects of EDS have been investigated. Within 48 h of the start of daily hCG treatment the number of nuclear profiles of Leydig cells (henceforth called relative number of Leydig cells) had increased from 1014 ± 40 to 1368 ± 30 cells per 1000 Sertoli cell nuclei. Previous experiments have indicated that these newly formed Leydig cells probably develop from differentiating Leydig cell precursors. When EDS is administered concomitantly with the third injection of hCG (2 days after the start of hCG treatment), the relative number of Leydig cells surviving EDS treatment was 388 ± 52 per 1000 Sertoli cells. Hence, there is a similarity between the increase in the relative number of Leydig cells after 2 days of hCG treatment and the relative number of EDS-resistant Leydig cells. The Leydig cells that survived EDS administration showed characteristics which also occur in developing Leydig cells in the immature testis. It is concluded that, in rats pretreated with hCG for 2 days before EDS administration, new Leydig cells with some immature characteristics are formed. One of these characteristics is that these cells are insensitive to EDS.
Journal of Endocrinology (1992) 134, 85–90
3β-Hydroxysteroid dehydrogenase inhibitor reduces ovarian steroid production but increases ovulation rate in the ewe: interactions with gonadotrophins and inhibin
Authors: Webb R. , Baxter G. , McBride D. , McNeilly A. S. 
Published: December 2008

ABSTRACT
Two experiments were carried out during the breeding season in ewes, first to investigate the effects of oral administration of a 3β-hydroxysteroid dehydrogenase (3β-HSD) inhibitor (epostane) on the number of corpora lutea, and secondly to investigate the mechanism through which epostane acts.
In the first experiment Dorset Horn ewes were treated orally with 25, 50, 100 or 200 mg epostane twice daily between days 10 and 15 of the oestrous cycle. All doses of epostane resulted in an increase in the number of corpora lutea per ewe, although the response was curvilinear, with the 25 mg dose showing the largest response and the 200 mg group the smallest response. Although there was no difference between groups in the number of ewes showing oestrus, the higher doses of epostane had a detrimental effect on fertility.
In the second experiment Welsh Mountain ewes were treated twice daily with 25 mg epostane from day 10 of the oestrous cycle and the ovaries were removed for analysis during either the luteal or the follicular phases. Treatment significantly increased the number of follicles >6 mm in diameter, but significantly reduced in-vitro follicular oestradiol and testosterone production. Despite a marked increase in peripheral inhibin concentrations there was no effect on in-vitro inhibin production. Epostane treatment also caused a significant reduction in peripheral FSH concentrations and an increase in mean LH concentration. The latter was due to an increase in LH pulse frequency during the luteal phase and LH pulse amplitude during the follicular phase.
These results confirm that treatment of ewes with epostane orally has a significant effect on follicular steroidogenesis and causes a significant increase in the number of corpora lutea per ewe. This effect on ovulation rate is not via an increase in peripheral FSH concentration, but may be caused by a reduction in follicular steroid activity either directly on the ovary or via an alteration in the pattern of LH secretion.
Journal of Endocrinology (1992) 134, 115–125
Radioimmunoassay of insulin-like growth factor-binding protein-6 in human serum and other body fluids
Authors: Baxter R. C. , Saunders H. 
Published: December 2008

ABSTRACT
A radioimmunoassay has been established for the insulin-like growth factor-binding protein, IGFBP-6, isolated from a human transformed fibroblast cell-line. The binding proteins IGFBP-I and IGFBP-3 did not cross-react, but both IGF-I and IGF-II markedly inhibited IGFBP-6 tracer binding to antiserum. This inhibition, greater for IGF-II than for IGF-I, was fully reversed by the addition of IGFBP-3 to sequester the IGFs. After fractionation of human serum and follicular fluid samples by gel chromatography, interference in the radioimmunoassay by fractions corresponding to the 150 kDa IGF-IGFBP complex could be eliminated by IGFBP-3. The equivalent fractions from cerebrospinal fluid and amniotic fluid fractionation did not interfere in the assay. The mean IGFBP-6 level in adult human serum was 0·221 ±0·110 mg/l, with values significantly higher in men than women, and slightly decreased in pregnancy. Similar values were seen in umbilical cord serum and in amniotic and follicular fluid samples, while the mean level in cerebrospinal fluid was slightly lower, 0·152±0·049 mg/l. This assay will facilitate studies on the regulation of IGFBP-6 production, and its role as an IGF carrier.
Journal of Endocrinology (1992) 134, 133–139