bluuebunny/crossref_metadata_2025_split huggingface dataset:
IS OXYTOCIN OF CONCEPTUS ORIGIN INVOLVED IN INHIBITION OF LUTEAL REGRESSION IN EARLY PREGNANCY IN EWES?
Authors: Lacroix M.C. , Charpigny G. , Reinaud P. 
Published: December 2008

ABSTRACT
This study describes the presence in and production by the ovine conceptus of an oxytocin-like peptide during the early stages of development. Oxycotin was measured by radioimmunoassay in ovine conceptuses from days 14 to 30 of pregnancy. Tissue concentrations of oxytocin increased from day 14 (24.8 ± 5 pg/100 mg) until day 19 (122.9 ± 52 pg/100 mg) and then decreased (3 ± 1 pg /100 mg). Oxytocin was released into culture medium by day-15 ovine conceptuses at a rate of 262 ± 55 pg/24 h. Reverse-phase high-performance liquid chromatography (HPLC) analysis of peptides extracted from a pool of ovine conceptuses was conducted using chromatographic conditions developed to separate oxytocin from other nonapeptides. Radioimmunoassay of HPLC fractions for oxytocin revealed an immunoactive conceptus peptide in a single fraction at the same retention time as chromatographed authentic oxytocin. Radioimmunoassay and chromatographic data therefore suggest that this oxytocin-like peptide is similar, if not identical, to authentic oxytocin. Concentrations of oxytocin in conceptus tissue were maximal during the period of inhibition of luteal regression (days 14-19). It is proposed that conceptus oxytocin is involved in the maintenance of luteal function in early pregnancy.
Increase in plasma concentrations of atrial natriuretic peptide during infusion of hypertonic saline in conscious newborn calves
Authors: Amadieu-Farmakis M. , Giry J. , Barlet J.-P. 
Published: December 2008

ABSTRACT
Plasma concentrations of atrial natriuretic peptide (ANP), plasma renin activity (PRA), plasma concentrations of aldosterone, urine flow rate and sodium and potassium excretion were studied in two groups of four conscious 3-day-old male calves, infused with hypertonic saline or vehicle. Hypertonic saline infusion (20 mmol NaCl/kg body weight) was accompanied by a progressive rise in plasma concentrations of ANP (from 16·5 ± 0·2 pmol/l at time 0 to 29·3 ± 3·0 pmol/l at 30 min; P< 0·05) and by a gradual decrease in PRA (from 1·61±0·23 nmol angiotensin I/1 per h at time 0 to 0·54± 15 nmol angiotensin I/1 per h at 90 min; P<0·05); there was no change in the plasma concentration of aldosterone. Within the first 2 h of the 24-h urine collection period there was a marked rise in urine flow rate and sodium excretion in treated calves when compared with control animals (66·0 ± 8·3 vs 15·9±1·2 ml/kg body weight per 2 h (P<0·05) and 6·7±1·3 vs 0·4±0·02 mmol/kg body weight per 2 h (P<0·01) respectively). During the following 22 h, urinary water and sodium excretion remained at significantly high levels.
Thus, in the conscious newborn calf, changes in plasma ANP levels and urinary water and sodium excretion during hypertonic saline infusion are compatible with the hypothesis that endogenous ANP participates, at least in part, in the immediate diuretic and natriuretic renal response induced by the sodium overload.
J. Endocr. (1988) 119, 23–29
Diminution of pulsatile growth hormone secretion in the domestic fowl (Gallus domesticus): evidence of sexual dimorphism
Authors: Johnson R. J. 
Published: December 2008

ABSTRACT
Temporal plasma GH secretory patterns were measured in cannulated male and female meat-type chickens of two commercial strains at 17, 38 and 60 days of age. Pulse height, amplitude and baseline values were similar in both male and female chickens at 17 days of age, with high amplitude and low baseline values. However, by 38 days of age pulsatile GH secretion was not detectable in females, whereas males exhibited a continued pulsatile secretory pattern similar to that at 17 days of age. Pulsatile GH secretion was not evident in either males or females at 60 days of age. These results clearly demonstrate a sexually dimorphic ontogeny of GH secretion in meat-type chickens.
J. Endocr. (1988) 119, 101–109
Comparison of some biological effects of epidermal growth factor and commercial serum albumin on the induction of α-lactalbumin in rat and rabbit mammary explants
Authors: Nicholas K. R. , Sankaran L. , Kulski J. K. , Chomczynski P. , Qasba P. 
Published: December 2008

ABSTRACT
Commercial preparations of serum albumin from six species can markedly enhance the prolactin-independent induction of α-lactalbumin in mammary explants from pregnant rats, and evoke such induction in the tissue from virgin rats. These effects are similar to those of epidermal growth factor (EGF) reported previously. The stimulatory activity of bovine serum albumin (BSA) resides in a putative impurity in the albumin. Charcoal extraction and gel filtration of the BSA results in complete loss of activity. Of the five milk protein mRNAs studied, only α-lactalbumin mRNA is induced by insulin, glucocorticoid and serum albumin in the absence of prolactin. Despite these similarities, the biological effects of serum albumin and EGF on mammary tissue diverge in some respects. They appear to operate by different mechanisms since their effects on the rat system are additive. Furthermore, while both inhibit prolactin-mediated induction of α-lactalbumin in rabbit mammary explants, cortisol converts EGF into a stimulatory agent, but merely blocks the inhibitory effect of serum albumin. The results emphasize that commercial serum albumin is not to be regarded simply as an inert protein additive to culture media.
J. Endocr. (1988) 119, 133–139
Pregnanediol excretion in fertile women: age-related changes
Authors: Metcalf M. G. , Livesey J. H. 
Published: December 2008

ABSTRACT
In normal women reproductive capacity diminishes with age; the decline has been detected before the start of the menopausal transition. It is known that in premenopausal women most menstrual cycles are ovulatory. An investigation was set up to examine the possibility that there is an age-related decline in the ability of the corpus luteum to secrete progesterone at this time.
Once-weekly urine samples for the measurement of pregnanediol were collected from 100 women aged 20–48 years, all of whom had regular 20- to 35–day menstrual cycles (1124 samples collected during the course of 312 menstrual cycles of which 96·8% were ovulatory). Pregnanediol excretion rates parallel the levels of progesterone in plasma. Examination of the rank correlation between age and pregnanediol excretion identified a significant negative correlation during the early and mid-follicular phases, but failed to detect any age-related change during the luteal phase.
The evidence does not support the concept of an age-related increase in luteal phase defects before the start of the menopausal transition.
J. Endocr. (1988) 119, 153–157
Characterization of circulating pro-opiomelanocortin-related peptides in human septic shock
Authors: McLoughlin L. , Evans S. F. , Watson J. D. , Hinds C. J. , Rees L. H. 
Published: December 2008

ABSTRACT
The nature of circulating pro-opiomelanocortin (POMC)-related peptides was investigated in patients with a diagnosis of septic shock. Also, changes following administration of methylprednisolone were monitored using established chromatographic techniques and three radioimmunoassays directed towards the N-terminal, mid-portion and C-terminal regions of the precursor.
Adrenocorticotrophin and β-endorphin-like peptides were identified in the circulation. By 60 min after a pharmacological dose of methylprednisolone (30 mg/kg) concentrations of these peptides were reduced and continued to fall up to 180 min. β-Lipotrophin and N-terminal POMC(1–76) were also detected by the β-endorphin and γ3-MSH assays respectively. The concentrations of these peptides were noticeably reduced only after 180 min.
The 31 000 Da MSH/ACTH/β-endorphin (POMC) and the 22 000 Da MSH/ACTH precursors were also present in the circulation in septic shock and their concentrations increased following steroid treatment.
J. Endocr. (1988) 119, 159–165
Relationship between zonal distribution of microsomal cytochrome P-450s (P-45017α,lyase and P-450C21) and steroidogenic activities in guinea-pig adrenal cortex
Authors: Shinzawa K. , Ishibashi S. , Murakoshi M. , Watanabe K. , Kominami S. , Kawahara A. , Takemori S. 
Published: December 2008

ABSTRACT
In an attempt to elucidate the functional role of the three zones of the adrenal cortex, the localization of microsomal cytochrome P-450s (P-45017α,lyase and P-450C21) and their relation to steroidogenesis in the guinea-pig adrenal cortex were studied. The intracellular localization and zonal distribution of P-45017α,lyase and P-450C21 were examined by the direct peroxidase-labelled antibody technique. The cytochromes were localized immunocytochemically on the smooth-surfaced endoplasmic reticulum. P-45017α,lyase was found to be distributed in the zona fasciculata, especially in the externa, and less in the zona reticularis. The zona glomerulosa was negative for immunohistochemical staining for P-45017α,lyase. In contrast, P-450C21 was distributed in all three zones in the adrenal cortex.
The cytochrome P-450 contents and their steroidogenic activities were determined with microsomes prepared from the outer zone (zonae glomerulosa and fasciculata) and from the inner zone (zona reticularis) of guinea-pig adrenals. Using an enzyme-linked immunosorbent assay, the ratio of P-450C21 content in the inner zone to that in the outer zone microsomes was estimated to be 1 ·24. 21-Hydroxylase activity was higher in the inner zone microsomes, which was in good agreement with the relative P-450C21 contents. The ratio of P-45017α,lyase content in the inner zone to that in the outer zone microsomes was estimated to be 0·75. 17α-Hydroxylase and C17–20-lyase activities were five- to sixfold greater in the outer than in the inner zone microsomes, which could not be explained by the P-45017α,lyase contents in the two zones.
The effects of ACTH on the zonal distribution of microsomal cytochrome P-450s and their steroidogenic activities were also investigated.
J. Endocr. (1988) 119, 191–200
Evidence of a functional aromatase system in the pituitary gland of the chick embryo in vitro
Authors: Guennoun R. , Gasc J.-M. 
Published: December 2008

ABSTRACT
The in-vitro effects of oestradiol and testosterone, alone or together with an aromatase inhibitor (1,4,6-androstatriene-3,17-dione), on the appearance of progesterone receptor (PR) in the pituitary were studied in the chick embryo. Whole pituitary glands from 10-day-old embryos were cultured for 2 days in a hormonally defined medium. The oestrogenic activity of the hormone added to the medium was determined by the induction of PR in nuclei of pituitary cells. Cells containing PR were identified by immunohistochemistry with an antibody to PR. Pituitary cells contained PR in their nuclei after 48 h of incubation with oestradiol or testosterone (0·1 μmol/l). Dihydrotestosterone failed to induce PR in pituitary cells, as did testosterone if the aromatase inhibitor was added to the culture medium. It is concluded that testosterone is aromatized locally at the level of the pituitary and, consequently, acts through the oestradiol receptor to induce the appearance of PR in pituitary cells.
J. Endocr. (1988) 119, 229–232
Early secretion of chorionic gonadotrophin by marmoset embryos in vivo and in vitro
Authors: Hearn J. P. , Hodges J. K. , Gems S. 
Published: December 2008

ABSTRACT
The control mechanisms of early pregnancy in primates differ from those in non-primate species in the early secretion of chorionic gonadotrophin (CG) by the embryo and in the support of the corpus luteum. This study describes the initiation of secretion of CG by the embryo of the marmoset monkey examined in vivo and in vitro. A bioassay for gonadotrophin, which did not distinguish between CG and LH, was adapted and validated for the marmoset. A system of embryo culture was developed whereby embryos were grown from morula/blastocyst stages until at least the differentiation of the trophoblast and yolk sac, facilitated by the embryo attaching to a monolayer of marmoset fibroblast cells. Gonadotrophin concentrations were measured in the peripheral circulation of marmosets during precisely timed stages during the first 84 days of the 144-day gestation period, providing a profile of secretion that was maintained at high levels for longer than the profile seen in Old World primates, including man. A clear increase above baseline levels was seen by day 17 after ovulation, implantation commencing in the marmoset on days 11–13. Gonadotrophin was secreted by embryos in culture from the time of attachment in vitro, but there was no clear evidence of secretion before attachment. Levels of gonadotrophin secreted by embryos in vitro increased rapidly, reaching a maximum mean production rate of 90 mIU/24 h within 4 days after attachment. The experimental systems developed here will allow the examination of the local function of CG at the implantation site, intra-embryonic control of its secretion and its possible involvement in embryonic development.
J. Endocr. (1988) 119, 249–255
Increases in plasma concentrations of steroids in the rat after the administration of caffeine: comparison with plasma disposition of caffeine
Authors: Pollard I. 
Published: December 2008

ABSTRACT
It was demonstrated that the altered endocrine environment caused by caffeine consumption could be equated with a stress-like pattern of response. A single acute treatment with caffeine (30 or 60 mg/kg) to male rats approximately 85 days old caused plasma concentrations of corticosterone, progesterone, testosterone and Na+ to rise significantly above control values. These changes were evident 3 min after caffeine administration and were maintained for 1–4 h before returning to normal. In animals exposed to daily chronic caffeine treatment for 10 days or more the levels of progesterone fell and Na+ rose significantly compared with control values at 24 h after administration. Following a single treatment of 30 mg/kg, caffeine was detected in blood plasma after 3 min, and reached peak levels by 1 h. After 24 h, less than 2% of the peak levels of caffeine remained. Metabolites of caffeine were detectable within 6 min and reached their peak levels 4 and 12 h later for theophylline and theobromine respectively.
It is suggested that high steroid levels may in the long-term cause an altered hepatic clearance pattern affecting both steroid metabolism and caffeine elimination. A preliminary study of the morphology of livers from males chronically exposed to caffeine revealed that the hepatic cells lost cytoplasmic matrix, and that the sinusoids did not show up as clear spaces, compared with those in the controls.
J. Endocr. (1988) 119, 275–280
Failure of acid–ethanol treatment to prevent interference by binding proteins in radioligand assays for the insulin-like growth factors
Authors: Mesiano S. , Young I. R. , Browne C. A. , Thorburn G. D. 
Published: December 2008

ABSTRACT
Acid–ethanol precipitation and gel filtration at acidic pH have been widely used to extract circulating binding proteins for insulin-like growth factor (IGF-I and IGF-II) from plasma or serum samples before radioligand assay for the respective IGFs. Gel filtration on Sephadex G-50 at neutral pH of neutralized acid– ethanol extracts of fetal and adult ovine plasma which had been incubated with 125I-labelled IGF-I or 125I-labelled IGF-II revealed that significant amounts of the IGF-binding protein activity survived the acid– ethanol extraction procedure.
Radioimmunoassay for IGF-I in acid–ethanol extracts of plasma samples from fetal, neonatal and adult sheep yielded results which depended upon the method used for separation of the antibody-bound IGF-I tracer from the free IGF-I tracer. Acid gel filtration of ovine fetal and adult plasma was found to remove completely the IGF-binding protein activity. Radioimmunoassay for IGF-I in samples of fetal, neonatal and adult sheep plasma that had undergone acid gel chromatography yielded consistent results for both methods that were used to separate antibody-bound IGF-I tracer from the free tracer.
Radioreceptor assays for IGF-II were similarly highly perturbed by the presence of binding protein in acid–ethanol extracts of ovine fetal and adult plasma. We conclude that acid–ethanol extraction can not be used reliably for the removal of IGF-binding proteins, and that only acid gel filtration is a completely safe and valid method.
J. Endocr. (1988) 119, 453–460
Insulin-like growth factor (IGF)-II and insulin, but not IGF-I, are mitogenic for fetal rat adrenal cells in vitro
Authors: van Dijk J. P. , Tanswell A. K. , Challis J. R. G. 
Published: December 2008

ABSTRACT
The agents controlling growth of the fetal adrenal gland are poorly defined. The purpose of the present study was to determine the factors required to promote proliferation of adrenal cells obtained from fetal rats at 20 days of gestation and grown in monolayer cell culture under serum-free conditions. Insulin stimulated [3H] thymidine incorporation into DNA at all concentrations (0·01–10 mg/l) tested. Rat insulin-like growth factor (IGF)-II in the presence of insulin promoted a dose-dependent increase in mitogenic activity, with a half-maximal concentration of approximately 1 μg/l; IGF-II had no effect in the absence of insulin. There was no significant effect of IGF-I on mitogenic activity in the presence or absence of insulin. Adrenal cell DNA synthesis was not stimulated by ACTH, several ACTH-related peptides, a variety of known growth factors, several steroids, or conditioned medium from fetal adrenal cells. We conclude that in the presence of insulin, IGF-II is a specific growth factor for the fetal rat adrenal. We also suggest that rat fetal adrenal cells, in common with other epithelial cell types under serum-free culture conditions, may respond to this progression factor without an obligatory requirement for an initial exposure to competence factors.
J. Endocr. (1988) 119, 509–516
Effect of melatonin on the peripheral concentrations of LH and progesterone after oestrus, and on conception rate in ewes
Authors: Wallace J. M. , Robinson J. J. , Wigzell S. , Aitken R. P. 
Published: December 2008

ABSTRACT
It has previously been shown that administration of the indoleamine melatonin to advance the breeding season of ewes is also associated with an increase in ovulation rate and subsequent litter size.
Experiment 1 assessed whether, in ewes receiving melatonin to advance the breeding season, the indoleamine acts directly on the corpus luteum to enhance progesterone secretion or indirectly through increased activity of the hypothalamic pulse generator. Six ewes received 3 mg melatonin orally at 15.00 h daily from 22 March onwards, six were induced to ovulate during mid-anoestrus following withdrawal of a progestagen pessary and injection of exogenous gonadotrophin and six acted as naturally ovulating controls. First overt oestrus occurred between 17 May and 8 July in melatonin-treated ewes, between 21 October and 3 January in control ewes and on 8 July in all induced ewes. On days 2 and 10 after the first overt oestrus, melatonin-treated ewes had pulsatile LH activity characteristic of that measured in control ewes ovulating naturally during the breeding season. There was an absence of any pulsatile LH activity in the induced ewes. Progesterone concentrations between days 7 and 12 following oestrus were significantly higher in melatonin-treated than in control and induced ewes, suggesting a luteotrophic role for melatonin.
Experiment 2 was carried out to determine whether administration of melatonin commencing after induced ovulation and insemination would alter the endocrine status of the ewe and thereby influence the establishment of pregnancy and embryo survival. Thirty-two anoestrous ewes were induced to ovulate on 29 June. Starting 24 h after intra-uterine insemination, 16 ewes were given melatonin daily for 60 days and 16 acted as controls. Daily LH concentrations were higher in melatonin-treated than in control ewes from days 2 to 22 after oestrus, while prolactin concentrations declined in melatonin-treated ewes over the same period. Plasma progesterone concentrations were enhanced in melatonin-treated ewes between days 4 and 9 following oestrus, yet ovulation rates were the same as for controls. Successful pregnancies occurred in 0·56 control (9 of 16) and 0·69 melatonin-treated (11 of 16) ewes. For these ewes the number of fetuses surviving to term as a proportion of ovulation rate was 0·43 and 0·51 for the control and melatonin treatment respectively.
J. Endocr. (1988) 119, 523–530
Localization of α-interferon in the human feto-placental unit
Authors: Howatson A. G. , Farquharson M. , Meager A. , McNicol A. M. , Foulis A. K. 
Published: December 2008

ABSTRACT
The distribution of α-interferon in human placental tissue was investigated by immunocytochemical study of paraffin wax-embedded tissue sections using a sheep α-interferon antiserum. Fifty-eight placentas of gestational ages from 8 to 40 weeks were examined.
α-Interferon was present in the syncytiotrophoblast of the chorionic villi of all placentas and was also in macrophages in 28 cases. The appearances suggest production of interferon in human placental trophoblast and, in view of its diverse biological effects, support the concept of a role for α-interferon in the complex series of events required for successful gestation.
J. Endocr. (1988) 119, 531–534
Actions of synthetic parathyroid hormone-related protein(1–34) on the isolated rat kidney
Authors: Ebeling P. R. , Adam W. R. , Moseley J. M. , Martin T. J. 
Published: December 2008

ABSTRACT
The isolated perfused rat kidney was used to study the effects of parathyroid hormone-related protein (PTHrP) on renal cyclic AMP (cAMP) and electrolyte excretion. A perfusate of PTHrP(1–34) increased cAMP excretion from 0·14 ± 0·09 (s.e.m.) nmol/l glomerular filtrate (GF) in controls to 24·67 ± 5·14 (P < 0·01) and decreased calcium excretion from 0·278 ± 0·033 to 0·162 ± 0·011 μmol/l GF (P < 0·01). Human PTH(1–34) (0·7 nmol/l) caused no significant change in calcium excretion, whilst the rise in cAMP excretion was similar to that with PTHrP. PTHrP(1–34) (7 nmol/l further increased cAMP production to 366·7 ± 100·8 nmol/l GF (P < 0·01), higher than the rise with hPTH(1–34) (7 nmol/l) which was 76·7 ± 46·8 (P < 0·05). With the higher concentrations of both peptides (7 nmol/l), calcium excretion was further reduced to 0·090 ± 0·009 μmol/l GF (P < 0·01), whilst phosphate excretion increased with both PTHrP and PTH. PTHrP (7 nmol/l) caused a fall in urinary pH compared with controls (P < 0·05). At low and high concentrations of both hormones, urinary pH was lower with PTHrP than hPTH (P < 0·01). Thus PTHrP, like PTH, acts on the kidney to increase cAMP and phosphate excretion and reduce calcium excretion, but PTHrP may be more effective. Disparate effects on urinary pH could be reflected in the clinical features of humoral hypercalcaemia of malignancy.
Journal of Endocrinology (1989) 120, 45–50