bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma concentrations of vasopressin and a prostaglandin F2α metabolite in women with primary dysmenorrhoea before and during treatment with a combined oral contraceptive
Authors: Hauksson A. , Åkerlund M. , Forsling M. L. , Kindahl H. 
Published: December 2008

ABSTRACT
Oral contraceptives reduce menstrual pain but the interaction with vasopressin and prostaglandin F2α, two uterine stimulants related to the condition, is unknown. Ten women with a history of moderate to severe dysmenorrhoea were studied. Repeated blood samples were taken during a first menstrual cycle without treatment, during the first 21 days of a second cycle when they received an oral contraceptive (150 μg levonorgestrel and 30 μg ethynyloestradiol) and on the first or second day of the bleeding following hormonal withdrawal. Measurements were made of plasma concentrations of arginine vasopressin, 15-keto-13,14-dihydroprostaglandin F2α, oestradiol-17β, progesterone, ethynyloestradiol, levonorgestrel, FSH, LH and prolactin, and serum osmolality was measured. Seven of the women rated their discomfort as moderate to severe on the first two menstruations, but as none or light at the withdrawal bleeding; with the rating scale for degree of pain that was used, this decrease in pain was significant (P< 0·001). The plasma concentration of vasopressin in these seven women showed significant variation, with the highest concentrations being obtained at the beginning of the two painful menstruations (3·76 ± 0·76 and 1·75 ± 0·30 (s.e.m.) pmol/l and at ovulation in the control cycle (1·91±0·58 pmol/l). During treatment the concentrations were consistently low, except on the first day of withdrawal bleeding (2·33±0·35 pmol/l). The concentrations of the prostaglandin F2α metabolite showed less variation, but again the values at withdrawal bleeding (271 ± 39 pmol/l) were not different from those obtained over the painful menstruations (255 ± 24 and 217 ± 25 pmol/l. The plasma concentrations of ovarian and adenohypophysial hormones, as well as osmolality, were normal throughout. The remaining three women had no, or only slight, menstrual pain in the control cycle and no menstrual peaks in the concentration of vasopressin or prostaglandin F metabolite. The present results gave no evidence for a reduced release of vasopressin and/or prostaglandin F2α that could explain the beneficial effect of oral contraceptives in dysmenorrhoea. Instead, it is possible that this effect is due to a decreased sensitivity of the uterus to these factors.
J. Endocr. (1987) 115,355–361
Age-related release of prolactin by the pituitary and the pituitary-hypothalamic complex in vitro: an attempt to describe the development of the hypothalamic prolactin-inhibiting and -releasing activities in male rats
Authors: Karanth S. , Dutt A. , Juneja H. S. 
Published: December 2008

ABSTRACT
We have recently demonstrated that the pituitary hypothalamic complex (PHC) is a good model for studying interactions between the hypothalamus and pituitary in vitro. The amount of prolactin secreted by the PHC is an index of prolactin secreted by the pituitary in the presence of hypothalamic control, while the amount released by the whole pituitary alone is an index of prolactin secreted in the absence of hypothalamic control. The amount of prolactin secreted by the PHC has been regarded as an index of hypothalamic prolactin-releasing activity (HPRA), while the difference in the amounts of prolactin secreted by the whole pituitary and the PHC is the hypothalamic prolactin-inhibiting activity (HPIA). Attempts were made to correlate HPRA and HPIA to the development of serum concentrations of prolactin from days 7 to 77 in male rats. The HPRA increased steadily from days 7 to 56, decreased significantly on day 63 and thereafter remained unchanged until day 77. The HPIA was low on days 7 and 14 and increased steadily up to day 49, with no further significant variations. The developmental patterns of HPRA and HPIA were comparable up to day 49. Serum concentrations of prolactin increased significantly until day 28 and remained fairly constant until day 49. The weight of the pituitary gland increased from 1·0± 0·03 mg (mean ± s.e.m.) on day 7 to 7·76 ± 0·32 mg on day 63 and remained unchanged thereafter. The weight of the hypothalamic islet was 31·5 ± 2·88 mg on day 7, 34·83 ±1·45 mg on day 14 and 50·4 ± 4·01 mg on day 21. After day 21 the weights of the hypothalamic islets were not significantly altered, except on day 49.
It was concluded that serum concentrations of prolactin are regulated by interaction or competition between HPRA and HPIA at the level of the pituitary.
J. Endocr. (1987) 115, 405–409
Administration of testosterone to wether lambs: effects on protein and energy metabolism and growth hormone status
Authors: Lobley G. E. , Connell A. , Buchan V. , Skene P. A. , Fletcher J. M. 
Published: December 2008

ABSTRACT
The effects of episodic infusion of testosterone into the vascular system on energy expenditure, nitrogen retention and whole body protein synthesis (determined from [1-14C]leucine kinetics) were studied in castrated male lambs under conditions of controlled food intake. Comparisons were made between a 10-day control period and a 10-day treatment period for each lamb. Infusion of testosterone produced a significant increase in heat production, but the magnitude (198 kJ/day, +2·5% was less than the differences in energy expenditure expected between entire and castrated male ruminants. The retention of nitrogen improved by 1·24 g/day ( + 22%) in response to the administration of androgen, and this was accompanied by a decrease in amino acid oxidation. Total protein synthesis also declined, and the anabolic nature of testosterone supply must, therefore, be effected through a reduction in the breakdown of protein, the mechanism being similar to that proposed for certain anabolic steroids and the β-agonist, clenbuterol. Contrary to other reports, the presence of testosterone had no effect on the plasma concentration of GH.
J. Endocr. (1987) 115, 439–445
Plasma gonadotrophin concentrations, pituitary gonadotrophin content and pituitary responsiveness to LHRH in rats treated with LHRH and oestradiol benzoate
Authors: Schuiling G. A. , Pols-Valkhof N. , Moes H. , Koiter T. R. 
Published: December 2008

ABSTRACT
Suppression of gonadotrophin secretion during prolonged treatment with a high dose of LHRH was studied. Long-term ovariectomized rats were infused for 6 days with various doses of LHRH (25, 50, 100, 250 or 500 ng/h) with or without simultaneous treatment with oestradiol benzoate (OB; 3 μg/s.c. injection); a further group was treated with OB only. The effects of these treatments were studied on plasma concentrations of LH and FSH, the pituitary content of LH and FSH and on LH and FSH secretion in vitro (perifusion) in the unstimulated state and following maximal LHRH stimulation (1 μg LHRH/ml perifusion medium).
Administration of LHRH caused a dose-dependent reduction in plasma concentrations of LH and FSH and depleted the pituitary LH/FSH stores. Treatment with OB lowered the plasma concentration of LH to about 30% and that of FSH to about 65% of the control values. Administration of OB plus a low dose of LHRH (25 or 50 ng/h) markedly stimulated the secretion of LH but not of FSH, so that the plasma concentrations of LH were fully restored to the control value. With higher rates of LHRH infusion, OB caused no enhancement of the plasma concentrations of LH and FSH.
The experiments in vitro revealed a sensitizing, i.e. stimulatory effect, of OB on LHRH-stimulated LH and FSH secretion. However, the higher the rate of infusion of LHRH the smaller the sensitizing effect. Interpolation from dose–response curves showed that an LHRH infusion rate of about 150 ng/h (which would establish a plasma concentration of LHRH of about 68 pmol/l) would have no effect. With still higher rates of infusion of LHRH, the effect of OB was either inhibitory (LH) or absent (FSH).
The present experiments show that, depending on dose and length of treatment, both LHRH and OB can have variable effects on the secretion of LH and FSH: LHRH, while depleting and desensitizing the pituitary gland, stimulates the release of LH, whilst OB, which is known to suppress the secretion of LHRH by the hypothalamus, augments the rates of unstimulated and LHRH-stimulated LH and FSH secretion. The augmenting effect of OB on the latter component of LH and FSH secretion can be suppressed with high doses of LHRH. However, these experiments also show that even with doses as high as 500 ng LHRH/h, infused continuously for 6 days, plasma concentrations of LH and FSH are not reduced by more than 60–70%.
J. Endocr. (1987) 115, 469–475
Regulation of major histocompatibility complex class II antigen expression by the FRTL-5 rat thyroid cell line
Authors: Weetman A. P. , Green C. , Borysiewicz L. K. 
Published: December 2008

ABSTRACT
We have used the continuously growing FRTL-5 rat thyroid cell line to examine the regulation of major histocompatibility complex (MHC) class II (or la) antigen expression. Of the various stimuli investigated, only the supernatant from activated T cells or recombinant γ-interferon induced Ia expression. All Ia-inducing activity was removed from the T cell supernatant by acid dialysis, suggesting that γ-interferon is the single critical mediator for class II antigen expression. Its action was not TSH dependent but expression of class II antigens increased from the G0-G1 to the S and G2 phases of the cell cycle, so that TSH enhanced Ia expression by its action on cell division. Other agents including lectins, hormones, epidermal growth factor, a calcium ionophore and a phorbol ester did not induce Ia expression. Substances known to inhibit murine macrophage Ia expression (cortisol, prostaglandin E2 and 5-hydroxytryptamine) had no effect on FRTL-5 Ia expression. The use of this thyroid cell line has permitted direct examination of modulators in the absence of any possible effects from contaminating non-thyroid cells present in primary cultures and the results suggest that, of the agents tested, only γ-interferon has significance in the context of Ia antigen expression by the thyroid.
J. Endocr. (1987) 115, 481–487
Thyroid status affects the regulation of prolactin mRNA accumulation by tri-iodothyronine and thyrotrophin-releasing hormone in cultured rat anterior pituitary cells
Authors: Wood D. F. , Docherty K. , Ramsden D. B. , Shennan K. I. J. , Sheppard M. C. 
Published: December 2008

ABSTRACT
The effects of tri-iodothyronine (T3) and TRH on prolactin mRNA accumulation in monolayer pituitary cell cultures prepared from both euthyroid and hypothyroid rats were investigated. Basal prolactin mRNA concentrations and prolactin release into culture medium were increased in hypothyroid cultures, the increase being related to the duration of hypothyroidism in vivo. The inhibitory effects of T3 seen in euthyroid cells were preserved in cells derived from hypothyroid animals, and the degree of inhibition was greater in cells from the most severely hypothyroid rats. However, the stimulation of prolactin synthesis and secretion induced by TRH in euthyroid cultures was not found in the hypothyroid cells. Hypothalamic and anterior pituitary TRH content were measured in similarly hypothyroid and euthyroid rats. A large hypothalamic pool of TRH was found, which was unchanged in hypothyroidism, whereas anterior pituitary TRH content was increased in the hypothyroid rats. The consequent down-regulation of anterior pituitary TRH receptors may explain the poor response of prolactin to TRH seen in vitro.
J. Endocr. (1987) 115, 497–503
INTERFERON SEQUENCE HOMOLOGY AND RECEPTOR BINDING ACTIVITY OF OVINE TROPHOBLAST ANTILUTEOLYTIC PROTEIN
Authors: Stewart H.J. , McCann S.H.E. , Barker P.J. , Lee K.E. , Lamming G.E. , Flint A.P.F. 
Published: December 2008

ABSTRACT
Sequencing of the 40 N-terminal amino acids of the blastocyst protein responsible for blocking corpus luteum regression in early pregnancy in sheep revealed a 37% homology with human α-interferon; 28% of the remaining amino acid changes were conservative. 125I-Labelled human α-interferon bound to membrane receptors from sheep uteri with an approximate Kd of 4 × 10−11 M; binding was inhibited by unlabelled α-interferon or purified blastocyst antiluteolytic protein. The blastocyst antiluteolytic protein therefore closely resembles the interferon-α family of antiviral proteins.
INHIBIN GENE EXPRESSION IN THE HUMAN CORPUS LUTEUM
Authors: Davis S.R. , Krozowski Z. , McLachlan R.I. , Burger H.G. 
Published: December 2008

ABSTRACT
We report inhibin α- and βA -subunit gene expression in the human corpus luteum and placenta using human α-subunit and bovine βA -subunit nucleic acid probes. In addition, we have demonstrated the presence of immunoreactive and bioactive inhibin in human corpora lutea. Our findings suggest that this tissue is a significant source of inhibin during the luteal phase of the normal human menstrual cycle.
Regulation of tyrosinase synthesis by α-melanocyte-stimulating hormone in hair follicular melanocytes of the mouse
Authors: Burchill S. A. , Virden R. , Fuller B. B. , Thody A. J. 
Published: December 2008

ABSTRACT
Tyrosinase activity was increased in hair follicular melanocytes of C3H-HeAvy mice during the hair cycle and reached higher levels on days 6–8 after plucking than on day 12. Similarly, the rate of incorporation of [35S]methionine into tyrosinase was greater on days 6–8 than on day 12, but the relative difference was much less. α-MSH had no effect on tyrosinase activity or the rate of [35S]methionine incorporation on day 12 and, while it increased both on days 6 and 8, it had a greater effect upon the latter. Pulse-chase experiments showed that the half-life of tyrosinase was 3·5 h and that this was unaffected by α-MSH.
The results indicate that the increases in tyrosinase activity which occur during the hair cycle involve changes in both the synthesis and activation of the enzyme and that the predominant effect of α-MSH is on the former of these two processes.
J. Endocr. (1988) 116, 17–23
Stimulation of chick adrenal steroidogenesis by avian parathyroid hormone
Authors: Rosenberg J. , Pines M. , Hurwitz S. 
Published: December 2008

ABSTRACT
Dispersed chick adrenocortical cells were incubated with avian parathyroid hormone (aPTH) or ACTH. Accumulation of cyclic AMP (cAMP), activity of cAMP-dependent protein kinase and the secretion of corticosterone and aldosterone, in response to these hormones, were measured.
Accumulation of cAMP and activity of cAMP-dependent protein kinase were stimulated by both aPTH and ACTH as well as by cholera toxin. Cyclic AMP production followed a similar time-course when stimulated by either peptide hormone. Stimulation of steroid hormone secretion was detectable after 20 min of incubation with ACTH, but only after 40 min with aPTH. The maximal steroid hormone secretion by adrenocortical cells was similar when induced by either peptide hormone. The aPTH concentrations needed for half-maximal response of corticosterone and aldosterone secretion were higher than those for ACTH (2·5- and 2-fold respectively), but still within the physiological range. The 11β-hydroxylase inhibitor metyrapone inhibited the secretion of both corticosterone and aldosterone when induced by either aPTH or ACTH.
The results suggest that aPTH is almost as potent as ACTH in stimulating the secretion of corticosterone and aldosterone from chick adrenocortical cells and utilizes a cAMP-dependent pathway similar to that of ACTH.
J. Endocr. (1988) 116, 91–95
Pulsatile administration of gonadotrophin-releasing hormone stimulates, in oestrogen-treated anaesthetized ovariectomized ewes, a surge release of LH qualitatively and quantitatively different from that induced by oestradiol in conscious ovariectomized ewes
Authors: Wright P. J. , Clarke I. J. 
Published: December 2008

ABSTRACT
The nature of the gonadotrophin-releasing hormone (GnRH) stimulus of the pituitary necessary for the oestrogen-induced plasma LH surge was studied in ovariectomized ewes. The sheep were treated with oestradiol benzoate (50 μg i.m.) at 0 h, and the hypothalamic contribution to the LH surge was blocked by pentobarbitone anaesthesia over the time during which the surge was expected (11–31 h). Pituitary responsiveness to exogenous GnRH (100 ng) administered i.v. in a pulsatile mode (once per hour or once per 20 min) over the period 15–30 h was assessed from plasma concentrations of LH. Neither of the GnRH treatments induced patterns of LH secretion similar to those seen in conscious ovariectomized ewes given oestrogen only. Plasma LH secretion in response to hourly GnRH pulses was less (P<0·01) than that associated with oestrogen-induced plasma LH surges in conscious control ewes. With pulses of GnRH administered every 20 min the amount of LH released was greater (P<0·05) than that in oestrogen-treated conscious control ewes. In contrast to the single surge induced by oestradiol in conscious ewes, GnRH pulses given every 20 min elicited phasic patterns of LH secretion consisting of two or three distinct surges. The failure of GnRH treatment to elicit an LH surge similar to an oestrogen-induced surge could reflect inappropriate GnRH treatment regimens, and/or inadequate priming of the pituitary with GnRH after induction of anaesthesia but before GnRH treatment.
J. Endocr. (1988) 116, 143–148
Effects of transplantation on mouse adrenal chromaffin cells
Authors: Jousselin-Hosaja M. 
Published: December 2008

ABSTRACT
The effects of long-term transplantation on the ultrastructure of adrenaline- and noradrenaline-storing cells from the adrenal medulla were determined using morphometric methods. Mouse adrenal medulla were freed from the adrenal cortex and grafted into the occipital cortex of the brain. Two types of chromaffin cells were identified by electron microscopy in grafts fixed with glutaraldehyde and osmium tetroxide. Noradrenaline-type cells were predominant and formed 70–80% of the surviving population of grafted chromaffin cells. A minority of the chromaffin cells contained medium-sized granules (140–210 nm in diameter) (medium granule cell; MGC) with finely granular moderately electron dense cores. Morphometric analysis of noradrenaline phenotype cells and MGC cells in transplants showed no significant differences compared with the noradrenaline-storing cells of normal adrenal glands. In contrast, noradrenaline-type cells and MGC cells in the grafts had areas of secretory vesicles which were significantly (P<0·01) larger and areas of rough endoplasmic reticulum which were significantly (P<0 ·01) smaller than those of the adrenaline-storing cells of normal adrenal glands.
It was concluded that long-term transplantation caused no degenerative changes in the ultrastructure of mouse adrenal chromaffin cells.
J. Endocr. (1988) 116, 149–153
Effects of passive immunization with antisomatostatin serum on plasma corticosterone concentrations in young domestic cockerels
Authors: Cheung A. , Harvey S. , Hall T. R. , Lam S.-K. , Spencer G. S. G. 
Published: December 2008

ABSTRACT
Young cockerels (6–8 weeks old) were injected with serum from sheep immunized against somatostatin-14 (anti-SRIF) or normal sheep serum (NSS). Blood samples were withdrawn periodically for the determination of plasma corticosterone concentration by radioimmunoassay. With frequent (every 10 min) sampling, NSS-treated control animals exhibited increased plasma corticosterone levels, presumably as a stress response to the experimental manipulation. Anti-SRIF stimulated a much greater increase in plasma corticosterone concentrations and a peak response was observed within 10 to 20 min, when the plasma corticosterone level reached more than twice that of the corresponding control value. With less frequent sampling, plasma corticosterone increased with anti-SRIF administration to as much as nine times the corresponding control value, and the peak response occurred much later. Under pentobarbitone anaesthesia, which itself increased basal corticosterone concentrations, anti-SRIF treatment promoted further increases in plasma corticosterone levels although to a smaller magnitude compared with conscious birds. The results suggest that endogenous somatostatin may play a role in the regulation of adrenocortical function in the domestic fowl. The mechanism of response may involve a central component.
J. Endocr. (1988) 116, 179–183
A comparison of the vasopressin response of rats to intraperitoneal and intravenous administration of hypertonic saline, and the effect of opioid and aminergic antagonists
Authors: Forsling M. L. , Matziari C. , Aziz L. 
Published: December 2008

ABSTRACT
The vasopressin response of rats to i.p. injection of hypertonic sodium chloride (1·5 mol/l) was compared with that following i.v. infusion of 1·05 mol sodium chloride/l. The two regimes produced a similar vasopressin response in terms of the osmotic threshold, although the slopes of the plot of plasma vasopressin levels against plasma osmolality were not identical. Pretreatment with naloxone and levallorphan increased the resting vasopressin levels and effectively potentiated vasopressin release in response to hypertonic saline by reducing the osmotic threshold for hormone release. Thus, opioid peptides appear to exert an inhibitory effect on vasopressin release under resting and stimulated conditions. The adrenoreceptor antagonists propanolol, phenyoxybenzamine and phentolamine produced a fall in resting vasopressin concentrations while propanolol and phenoxybenzamine potentiated the osmotic release of vasopressin in association with a fall in the osmotic threshold. This would suggest that noradrenergic pathways are excitatory at rest while having an inhibitory effect on the osmotic response. Metoclopramide also produced a fall in resting plasma vasopressin concentrations while increasing the osmotic response. In contrast haloperidol did not affect the vasopressin response.
J. Endocr. (1988) 116, 217–224
Association of progesterone with a unique particulate fraction of the human corpus luteum
Authors: Bramley T. A. , Menzies G. S. 
Published: December 2008

ABSTRACT
Homogenates of human corpus luteum were fractionated on continuous sucrose density gradients, with and without pretreatment with digitonin to perturb plasma membranes. Fractions of each gradient were assayed for steroid content and a range of plasma membrane and intracellular organelle markers. Progesterone and oestradiol were associated with a particulate fraction (buoyant density, 1·08–1·13 g/cm3). The buoyant density distribution of these steroids was distinct from those of the luteal cell plasma membrane and intracellular organelle markers tested. Treatment with digitonin increased the buoyant density of both progesterone and oestradiol. If steroids are contained in distinct vesicles, these vesicles may be involved in the sequestration of newly synthesized steroid and its movement to the cell surface for release into the circulation.
J. Endocr. (1988) 116, 307–312