bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diminished lymphocytic cortisol metabolism-enhancing effect in endogenous thyrotoxicosis
Authors: Grinblat J. , Klein A. 
Published: December 2008

ABSTRACT
A study was carried out to determine the effect on lymphocytic cortisol metabolism (LCM) of plasma from 62 patients with diffuse thyrotoxic goitre (DTG), 14 patients with toxic nodular goitre (TNG) and ten hypothyroid patients. Plasma of 33 healthy donors served as controls. A known concentration of human lymphocytes was incubated with cortisol in media containing 50% phosphate-buffered saline (PBS) and 50% of one of the following additions: (1) PBS, (2) homologous plasma (HP), (3) heterologous plasma, (4) plasma from DTG patients, (5) plasma from TNG patients, (6) plasma from hypothyroid patients, (7) PBS and HP to which l-thyroxine (T4) and tri-iodothyronine (T3) had been added separately and as a mixture up to a concentration ten times the normal, (8) boiled HP and (9) boiled DTG plasma. Plasma from hypothyroid patients gave an LCM-enhancing effect (LCMEE) similar to that of HP. The plasma of DTG and TNG patients had a markedly lesser effect on LCM than did HP. The T4 and T3 had no additional effect when added to PBS or HP. Boiling of HP and DTG plasma resulted in a similar decrease in LCMEE. The findings of this study raise the possibility of the existence of a factor inhibiting LCMEE in the plasma of thyrotoxic patients.
J. Endocr. 1984 101, 149–153
Effects of a long-acting analogue of LH releasing hormone on human and rat corpora lutea
Authors: Richardson M. C. , Hirji M. R. , Thompson A. D. , Masson G. M. 
Published: December 2008

ABSTRACT
Dispersed luteal cells were prepared both from samples of human corpora lutea obtained during normal menstrual cycles and from luteinized rat ovaries of animals pretreated with pregnant mare's serum gonadotrophin and human chorionic gonadotrophin (hCG). Addition of the long-acting analogue, d-Ala6-des-Gly10-LH releasing hormone ethylamide (d-Ala6-LHRH), to rat luteal cells caused a small but significant increase in progesterone production. An inhibitory action of the analogue on hCG-stimulated steroidogenesis by rat luteal cells was confirmed. Addition of d-Ala6-LHRH to suspensions of human luteal cells had no effect on either basal or hCG-stimulated progesterone production.
Studies on the interaction of 125I-labelled d-Ala6-LHRH with the dispersed cell preparations, while confirming the presence of displaceable binding to rat luteal cells, failed to detect any equivalent binding to human luteal cells. Low levels of displaceable binding observed using homogenates of human corpora lutea are interpreted as being of doubtful physiological significance in view of the negative findings obtained with the intact cell system.
J. Endocr. (1984) 101, 163–168
Electrophysiological and morphological cell polarity and iodine metabolism in cultured porcine and human (normal and Graves') thyroid cells
Authors: Takasu N. , Handa Y. , Shimizu Y. , Yamada T. 
Published: December 2008

ABSTRACT
In cultured porcine and human thyroid cells, electrophysiological and morphological studies showed that cultivation in the presence of TSH, prostaglandin E2 (PGE2) or dibutyryl cyclic AMP (dbcAMP) maintained normal cell polarity with iodine incorporation and organification. Cells cultivated in the absence of these substances had inverted cell polarity and lacked iodide incorporation.
In the presence of TSH, PGE2 or dbcAMP, the thyroid cells formed follicles with normal cell polarity and the microvilli pointed toward the follicle lumina. Intracellular resting potentials were − 60 mV and the electrical potentials in the follicle lumina were negative at − 20 mV. The transmembrane potential differences (p.d.) between the follicle lumina and the epithelial cells were − 40 mV and those between the epithelial cells and the culture media − 60 mV.
In the absence of TSH, PGE2 or dbcAMP, the thyroid cells formed 'domes' or hollow spheres with inverted cell polarity and the microvilli pointed toward the culture media. Intracellular resting potentials were − 40 mV, being less negative than those in the presence of TSH, PGE2 or dbcAMP. The electrical potentials in the 'dome' or hollow sphere cavities were positive at + 19 mV. The transmembrane p.d. between the culture media and the epithelial cells was − 40 mV and that between the epithelial cells and the cavities − 60 mV, indicating that electrophysiologically the cell polarity was inverted in the absence of TSH, PGE2 or dbcAMP.
No significant differences in electrophysiology and iodine metabolism were observed between normal and Graves' human thyroid cells in culture.
J. Endocr. (1984) 101, 189–196
Effect of ovariectomy and clomiphene on the in-vitro incorporation of [3H]thymidine into pituitary DNA and on prolactin synthesis and release in rats
Authors: Burdman J. A. , Calabrese M. T. , Romano M. I. , Carricarte V. C. , MacLeod R. M. 
Published: December 2008

ABSTRACT
In the anterior pituitary gland changes in prolactin synthesis and in the incorporation of [3H]thymidine into DNA are coincident under several experimental conditions. We investigated whether these changes are obligatory, thus indicating a regulatory mechanism common to the synthesis of both macromolecules. Alternatively, the parallel changes may represent similar responses to various stimuli operating through different pathways. The administration of α-methyl-p-tyrosine (αMpT) to rats stimulated the incorporation of [3H]leucine into prolactin and [3H]thymidine into DNA. When the effectiveness of oestrogen was suppressed by ovariectomy or by blockage of oestrogen receptors by the antioestrogen clomiphene, αMpT stimulated the synthesis of prolactin but not the incorporation of [3H]thymidine into pituitary DNA. The results clearly indicate two independent mechanisms regulating the synthesis of prolactin and DNA in the anterior pituitary gland.
J. Endocr. (1984) 101, 197–201
Adrenocorticotrophic hormone stimulation of mammary secretion in lactating goats independent of increased mammary uptake of glucose
Authors: Stewart H. J. , Thompson G. E. 
Published: December 2008

ABSTRACT
The treatment of lactating goats with ACTH (single intramuscular injection) or cortisol (systemic infusion) resulted in an increase in milk yield and in the secretion of lactose, citrate and glucose into milk. The concentration of glucose in arterial plasma was also increased, resulting in a greater supply of glucose to the mammary gland. After ACTH treatment mammary uptake of glucose from the circulation did not increase and the balance between mammary uptake of glucose from blood and mammary output of glucose 'equivalents' into milk was significantly reduced. The results show that ACTH and cortisol can increase milk yield and lactose secretion by altering mammary metabolism of glucose.
J. Endocr. (1984) 101, 203–211
Transport of oestrone sulphate by the mammary gland in the goat
Authors: Heap R. B. , Hamon M. , Fleet I. R. 
Published: December 2008

ABSTRACT
During pregnancy in goats the concentration of endogenous oestrone sulphate in milk increased more than twofold, and that in arterial and mammary venous plasma 10- and 20-fold respectively. The concentration in milk was higher than that in arterial plasma, particularly in lactating goats during mid-gestation. This was partly related to mammary production of oestrone sulphate (or of a closely related steroid which cross-reacted in the radioimmunoassay) since in tracer infusion studies the specific activity of oestrone sulphate in milk was significantly lower than that in arterial or mammary venous plasma. It was also related to the existence of a mechanism within the gland which concentrates oestrone sulphate in milk since when infused close-arterially into the mammary gland of a non-pregnant goat with undetectable levels of the endogenous compound in the circulation, a concentration ratio of 7·4:1·0 was reached for oestrone sulphate in milk: arterial plasma.
Tracer kinetic studies showed that mammary extraction of [3H]oestrone sulphate was variable (up to 41·3 ± 30·6%, mean ± s.e.m.). During intravenous or close-arterial infusion, radioactivity in arterial and mammary venous plasma at steady state was mainly in the form of [3H]oestrone sulphate (range, 64± 10·6 to 80·2 ± 5·9% of total radioactivity in plasma). The remainder was in the form of compounds chromatographically similar to oestradiol-17β-3-monosulphate, oestradiol-17α-3-monosulphate and unconjugated oestrogens. The distribution of radioactivity between these different steriods was similar in arterial mammary venous plasma indicating a low level of selective mammary metabolism or extraction. The amount of labelled oestrone sulphate transferred into milk was low, and it was significantly less in pregnant (range, 0·11 ±0·07 to 0·27 ± 0·16% of total infusate) than in non-pregnant animals (3·23±0·50%).
Studies of the rate of transfer of [3H]oestrone sulphate from blood to milk indicated the presence of a transcellular route with peak activity in milk occurring about 110 min after the start of the infusion.
J. Endocr. (1984) 101, 221–230
Effects of hysterectomy and in-vivo treatment with uterine extracts on plasma concentrations of growth hormone, thyrotrophin and thyroid hormones in rats: a kinetic study
Authors: Bíró J. , Eneroth P. , Ritzén E. M. 
Published: December 2008

ABSTRACT
Plasma concentrations of GH, TSH, tri-iodothyronine (T3) and thyroxine (T4) were measured in adult rats 2 and 4 weeks after ovariectomy and ovariohysterectomy. Two weeks after ovariohysterectomy, the concentration of GH was significantly higher, but TSH and T3 concentrations were significantly lower than in rats which had been ovariectomized only. Hysterectomy had no effect on plasma GH and TSH concentrations if it was performed 2 weeks after ovariectomy.
Plasma T3 had decreased by 2 weeks after ovariectomy but returned to pretreatment levels by 4 weeks. Recovery of the plasma T3 concentration was not observed if ovariectomy was followed by hysterectomy, since a further decrease of plasma T3 occurred. Plasma T4 was not significantly influenced either by ovariectomy or by ovariohysterectomy.
Steroid-free uterine extracts given i.p. to ovariohysterectomized rats reduced plasma GH within 24 h of injection.
Increases in plasma TSH, T3 and T4 were achieved in ovariohysterectomized rats with injections of uterine extracts (from intact, oestrogen-treated or castrated rats), but the increases were not consistent for the three hormones either as regards time after injection, nor for which particular extracts were effective.
It was concluded that the uterus may contain factors which influence the GH storage and secretion and TSH-thyroid regulation in rats.
J. Endocr. (1984) 101, 243–248
Metabolic regulation of somatomedin activity in rat liver
Authors: Vassilopoulou-Sellin R. , Phillips L. S. , Oyedeji C. O. , Samaan N. A. 
Published: December 2008

ABSTRACT
We have compared circulating and hepatic somatomedin (SM) activity in rats with diabetes or malnutrition of varying severity. Somatomedin activity was measured by the hypophysectomized rat costal cartilage bioassay. In both moderate diabetes and moderate malnutrition, mean serum SM activity was not significantly lower than normal (79 ± 13% (s.e.m.) and 95 ± 11% vs normal controls respectively). In contrast, liver perfusate SM activity was significantly reduced in both groups (51 ± 12% for moderate diabetes and 44 ± 12% for moderate malnutrition). Liver extract SM activity was also significantly decreased in both moderate diabetes and malnutrition (74 ± 4% and 75 ± 6% vs normal controls respectively). In severe diabetes and malnutrition, both liver and serum activities were low, consistent with previous reports. Our studies showed that liver SM activity fell in response to metabolic stress before a decrease in circulating levels occurred, supporting the concept that the liver regulates serum SM activity and growth in diabetes and malnutrition.
J. Endocr. (1984) 101, 257–261
Evaluation of the rat thyroid cell strain FRTL-5 as an in-vitro bioassay system for thyrotrophin
Authors: Bidey S. P. , Chiovato L. , Day A. , Turmaine M. , Gould R. P. , Ekins R. P. , Marshall N. J. 
Published: December 2008

ABSTRACT
The cyclic AMP response to bovine TSH was characterized in a strain of rat thyroid follicular cells (FRTL-5) maintained in continuous culture. Significant stimulation of intracellular cyclic AMP was attained at a TSH dose of 5 μu./ml. Cyclic AMP accumulation continued to increase, at higher TSH doses, with no evidence for attainment of a maximum level at the highest dose tested (5 mu./ml). The precision of TSH measurement was better than 10% over the range 50–5000 μu./ml, comparing favourably with that observed with analogous assays based on human cells, tissue slices or membrane preparations. Using sequential subcultures of FRTL-5 cells, the between-assay variation in response to a single dose of a standard preparation of bovine TSH (53/11; 370 μu./ml) was of the order of 20% which compared favourably with the between-assay variation observed with different cultures of human thyroid cells. Prolongation of the incubation of FRTL-5 cells with TSH to 3 h revealed a progressive increase in the extracellular accumulation of cyclic AMP. Addition of TSH to resting FRTL-5 cells resulted in a stimulation of inorganic iodide uptake with pronounced bell-shaped dose–response characteristics. Thus a maximum uptake was observed at a TSH dose of 100 μu./ml with a significant reduction at higher doses. Acute stimulation of cells with TSH (100 μu./ml) resulted in a rapid and marked alteration in cell morphology, with evidence of cellular retraction and surface ruffling.
J. Endocr. (1984) 101, 269–276
A quantitative relationship between conceptus number and ovarian steroid dehydrogenase activity in pregnant rats
Authors: Miyauchi F. , Kato H. , Yamashita H. , Ueda K. , Tamura H. , Mano T. , Torigoe T. 
Published: December 2008

ABSTRACT
The effects of a conceptus-derived substance on the activity of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 20α-HSD in the ovary were studied in the rat. On day 7 of pregnancy (day 1 = insemination), rats were laparotomized and the desired number of conceptuses was aspirated from the uterus; thus, rats carrying one, two, three, four, five to seven or eight to ten conceptuses were prepared. They were autopsied on day 15 and 3β-HSD and 20α-HSD activity in the corpus luteum (CL) or non-luteal ovarian tissue (NLO) was determined. Conceptus number was directly related to 3β-HSD and inversely related to 20α-HSD activity in the CL. The serum progesterone level and CL weight were also directly related to conceptus number. Neither 3β-HSD nor 20α-HSD activity in the NLO was affected by conceptus number. These results indicated that 3β-HSD and 20α-HSD in the CL are probably regulated by placental hormone secreted in proportion to the number of conceptuses; in the NLO these enzymes may be controlled by a different mechanism.
J. Endocr. (1984) 101, 285–288
Luteinizing hormone increases the number of ova shed in the cyclic hamster and guinea-pig
Authors: Garza F. , Shaban M. A. , Terranova P. F. 
Published: December 2008

ABSTRACT
Osmotic minipumps containing 400 μg ovine LH installed subcutaneously on day 1 (oestrus) of the cycle in the hamster induced superovulation of 30·0 ± 2·1 ova (n=5) at the next expected oestrus. Controls ovulated 12·0 ± 0·8 ova (n = 6). Bovine LH, human LH, porcine LH, human chorionic gonadotrophin and pregnant mare serum gonadotrophin were effective in approximately doubling the number of ova spontaneously shed in the hamster. Ovine FSH (200 μg/pump) was most effective in increasing the number of ova spontaneously shed (55 ± 6, n=5) in the hamster. Infusion of ovine LH on days 1–4 prevented the reduction of the number of antral follicles that occurs normally between days 3 and 4 of the 4-day cycle. Since this reduction in follicular numbers in control cyclic hamsters is due to atresia, the exogenous LH might prevent atresia of the developing follicles. In the hamster, exogenous ovine LH significantly increased the serum concentrations of androstenedione, oestradiol and LH but not of FSH. Hamsters were hypophysectomized on the day of oestrus, given immediate LH (400 pg) or FSH (200 μg) replacement therapy and autopsied on day 4. Ovarian histology revealed that immediate LH treatment after hypophysectomy sustained development of histologically normal preovulatory follicles but had no effect on the number of smaller sizes of follicles. Immediate FSH treatment after hypophysectomy increased only the number of smaller sized follicles. Since LH did not increase the smaller sized follicles, no 'FSH-like' effect on follicular development was observed. In the hamster, the ability of various preparations of LH to induce superovulation did not correlate with their ability to displace 125I-labelled ovine FSH from its ovarian binding sites. The superovulatory action of LH required the presence of the pituitary gland, indicating that LH might synergize with FSH and/or prolactin (or hamster LH) for spontaneous superovulation and it appears that exogenous LH might induce superovulation by prevention of atresia.
Infusion of LH into the guinea-pig beginning on day 12 of the cycle (day 1 is the day of ovulation) doubled the ovulation rate whereas in the cyclic rat and mouse LH treatment throughout the cycle was ineffective in increasing the number of ova shed.
J. Endocr. (1984) 101, 289–298
Developmental changes in the diurnal rhythm of secretion of corticosterone and LH in the domestic hen
Authors: Wilson S. C. , Jennings R. C. , Cunningham F. J. 
Published: December 2008

ABSTRACT
When diurnal changes in the plasma concentrations of corticosterone and LH were compared at various times during sexual development a diurnal rhythm in the secretion of corticosterone was most pronounced at 4·5 weeks of age in hens maintained on a schedule of 8 h light: 16 h darkness (8L: 16D) and at 8·5 weeks of age in hens maintained on 16L: 8D. At these ages the phase-angle of the rhythm in relation to the onset of darkness was 3 h earlier than had been observed in previous studies of the adult hen. The characteristics of the corticosterone rhythm changed during sexual development and diurnal changes were no longer evident in hens at 17 weeks of age at a time when prepubertal plasma concentrations of LH were maximal. However, there was a tendency for plasma concentrations of corticosterone to fluctuate diurnally in hens studied at less than 10 days before the onset of lay although not to the same extent as has previously been observed in the adult hen. This period of development was associated with a pronounced increase in the plasma concentration of progesterone. An increase in the plasma concentration of LH at the onset of darkness was observed at all ages in hens maintained on either photoschedule. In hens of 4·5–15 weeks of age maintained on 16L:8D or 8L:16D this increase in the plasma concentration of LH was sustained during the first 5 or 8–11 h of darkness respectively but at 17 weeks of age only a transient increase in LH was seen at the onset of darkness.
Plasma concentrations of LH in samples of plasma taken at intervals of between 3 days and 2 weeks throughout sexual development were, until 18–19 weeks, consistently higher in hens maintained on a photoschedule of 16L:8D than on 8L: 16D.
J. Endocr. (1984) 101, 299–304
Regulation of murine α1 -pregnancy-associated protein by gonadal steroids during the acute-phase response
Authors: Waites G. T. , Bell S. C. 
Published: December 2008

ABSTRACT
A pregnancy-associated serum protein of the mouse (α1-PAP) has recently been reported to be also synthesized by the non-pregnant female, but not the untreated male, in response to injury. The role of gonadal hormones in this phenomenon has been investigated. Ovariectomy abolished the ability of injury to induce synthesis of α1-PAP. Although administration to ovariectomized animals of oestradiol alone resulted in the appearance of low concentrations of α1-PAP after injury, injection of either progesterone or oestradiol plus progesterone permitted injury to induce concentrations of α1-PAP similar to those observed in intact injured females. Castrated mice, like intact males, failed to produce α1-PAP in response to injury, but administration of either oestradiol or oestradiol plus progesterone caused injury to induce concentrations of α1-PAP similar to those in injured intact females. Administration of testosterone to intact females abolished the α1-PAP response to injury and administration of oestradiol plus progesterone to intact males failed to induce the same response as in castrated males. These findings suggest that testosterone can inhibit the synthesis of α1-PAP in response to injury in both sexes whereas oestradiol and progesterone exhibit different abilities in males and females to facilitate the induction of α1-PAP synthesis by injury.
J. Endocr. (1984) 101, 315–318
An investigation of the involvement of calcium in the control of prolactin secretion: studies with low calcium, methoxyverapamil, cobalt and manganese
Authors: Merritt J. E. , Brown B. L. 
Published: December 2008

ABSTRACT
The possible role of calcium as a primary mediator in the control of prolactin secretion from normal pituitary cells was examined. Basal prolactin secretion, and secretion stimulated by thyrotrophin releasing hormone (TRH), raised K + or the calcium ionophore, A23187, were all dependent on the presence of extracellular Ca2+. The calcium channel antagonists, methoxyverapamil, cobalt and manganese, inhibited basal, TRH- and K+-stimulated prolactin secretion. In addition, prolactin secretion stimulated by a phosphodiesterase inhibitor, isobutylmethylxanthine, which increases cellular cyclic AMP, was inhibited by these Ca2+ antagonists. These observations indicate that Ca2+ may be the primary intracellular mediator in the control of prolactin secretion, with cyclic AMP having a secondary modulatory role on Ca2+ influx, probably on voltage-dependent Ca2+ channels.
J. Endocr. (1984) 101, 319–325
Does oxytocin play a role in the onset of maternal behaviour in the rat?
Authors: Bolwerk E. L. M. , Swanson H. H. 
Published: December 2008

ABSTRACT
Oxytocin is released during parturition and may also play a role in maternal behaviour. Oxytocin, injected in the cerebral ventricles, has been reported to accelerate the onset of maternal behaviour in oestrogen-pretreated virgin Sprague—Dawley rats within 2 h of injection. This study was an attempt to replicate and extend these findings in Wistar rats. In the first experiment, 16 virgin females were ovariectomized and a cannula was placed into the cerebral ventricle. Forty-eight hours after a single injection of 24 μg oestradiol benzoate (OB), 400 ng oxytocin or saline were injected into the ventricle. In the second experiment three groups were observed: an untreated control group plus two ovariectomized and cannulated groups treated with OB in a regimen designed to mimic pregnancy. After 10 days of OB administration they received an injection of either saline or oxytocin (400 ng) into the ventricle. Immediately after this injection they were exposed to the pups and observations started. In both experiments no rat became maternal in the first 1·5 h after the intracerebroventricular injection. Oxytocin therefore did not induce a rapid onset of maternal responsiveness in oestrogen-pretreated Wistar rats.
J. Endocr. (1984) 101, 353–357