bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatty acid synthesis by explant cultures from the mammary glands of goats on days 60 and 120 of pregnancy
Authors: Forsyth I. A. , Turvey A. 
Published: December 2008

ABSTRACT
Explants of mammary glands from 60-day pregnant goats showed a mean fourfold increase in fatty acid synthesis from acetate when cultured with insulin+ cortisol. Epithelial cells increased their area by 60% but no secretory activity was induced. In 120-day pregnant goats, fatty acid synthesis and epithelial cell area were greater than at day 60 of pregnancy and were unaffected by hypophysectomy or by daily treatment with bromocriptine from day 60. Neither increased further on culture of mammary explants in insulin + cortisol.
Ovine prolactin increased fatty acid synthesis two-fold when added to insulin + cortisol in cultures of mammary tissue from goats on day 60 of pregnancy and secretory activity was induced. On day 120 of pregnancy insulin + cortisol + prolactin sustained or slightly stimulated both fatty acid synthesis and the extensive secretion present in the tissue at the start of culture. Synthesis of medium-chain fatty acids of milk-fat was also sustained by prolactin in one goat.
An atmosphere of air was found to maintain normal histological structure of the mammary gland. By contrast, in 95% oxygen, explants from goats which were 60 days pregnant showed epithelial cells filling the lumina of ducts and alveoli in 60% of explants and a poor response to prolactin.
J. Endocr. (1984) 100, 87–92
Suppression of LH secretion by oestradiol, dihydrotestosterone and trenbolone acetate in the acutely castrated bull
Authors: Gettys T. W. , D'Occhio M. J. , Henricks D. M. , Schanbacher B. D. 
Published: December 2008

ABSTRACT
Twenty acutely castrated bulls were used to investigate the role of androgenic and oestrogenic steroids in the feedback control of LH secretion. The effects of 5α-dihydrotestosterone (DHT) or the growth stimulants trenbolone acetate (TBA) or oestradiol-17β (OE2) on serum LH secretory profiles were measured. In addition, pituitary LH responses to exogenous LH releasing hormone (LHRH) were determined to differentiate between hypothalamic and pituitary sites of steroid action. At the time of castration, two groups of animals were given implants of either 45 mg OE2 or 200 mg TBA. Another group received equivalent to 30 mg daily injections of DHT. Control steers showed an increase in LH from 2·4 ± 0·5 (s.e.m.) μg/l to 7·0 ± 0·5 μg/l during the week after castration. Treatment with DHT and TBA prevented the post-castration rise in serum LH. In contrast, steers given implants of OE2 showed a significantly greater increase in LH than controls 1 day after castration, but by day 5 LH declined in the OE2-treated group to precastration values. Five weeks after castration control steers secreted LH in pulses at intervals of 40–50 min and with an amplitude of 4·2± 0·4 μg/l. Pulses were not detected in the LH profiles of the steroid-treated steers. Dihydrotestosterone and TBA significantly reduced pituitary LH responses to exogenous LHRH, whereas steers receiving OE2 showed LH responses to LHRH which were similar to those observed in castrated controls.
These results support the hypothesis that androgenic and oestrogenic components participate separately in the feedback control of LH secretion in the bull. A similar LH response to exogenous LHRH in control and OE2-treated animals suggests that the primary site of oestrogen feedback is at the level of the hypothalamus. Conversely, the small LH response to LHRH in androgen-treated animals suggests that androgen feedback is, in part, imposed at the level of the pituitary gland. Interestingly, LH secretion is regulated by dosages of androgenic and oestrogenic steroids which are available commercially as growth stimulants for cattle.
J. Endocr. (1984) 100, 107–112
A water-soluble fragment of the thyroid-stimulating hormone receptor which binds both thyroid-stimulating hormone and thyroid-stimulating hormone receptor antibodies
Authors: Davies Jones E. , Rees Smith B. 
Published: December 2008

ABSTRACT
Previous studies have shown that freezing and thawing of human thyroid homogenates releases a water-soluble substance which reversibly binds to TSH-receptor antibodies. This substance has been designated long-acting thyroid stimulator absorbing activity (LAA). We now describe a new method for measuring LAA based on the TSH-receptor assay and application of the technique to the study of LAA.
Our results indicate that LAA is a heat-labile glycoprotein which co-elutes with haemoglobin on gel filtration. Furthermore, LAA is retarded by columns of Sepharose–TSH but not by Sepharose coupled to human chorionic gonadotrophin, normal immunoglobulin G or bovine serum albumin, suggesting that LAA contains a binding site for TSH as well as for TSH-receptor antibodies. It would seem therefore that LAA is a water-soluble fragment of the TSH receptor possibly resulting from proteolytic cleavage of the receptor at a site close to the cell surface.
J. Endocr. (1984) 100, 113–118
Central inhibition of milk ejection in the rabbit: involvement of hippocampus and subiculum
Authors: Tindal J. S. , Blake L. A. 
Published: December 2008

ABSTRACT
Removal of discrete parts of the forebrain of the anaesthetized lactating rabbit by suction caused repeated milk-ejection responses. These were associated with transection or removal of the subiculum, which represents the major efferent pathway from the hippocampal formation to the diencephalon. It is suggested that the hippocampus may exert a tonic, inhibitory influence over oxytocin release, that this inhibition may represent a cascade of events which originates in the brainstem and culminates in the subiculum and that removal of this inhibition may lead to release of oxytocin.
J. Endocr. (1984) 100, 125–129
Effect of glucose on insulin biosynthesis and β cell ultrastructure in cultured fetal rat pancreas
Authors: Milner R. D. G. , Cser A. , Cope G. H. 
Published: December 2008

ABSTRACT
Pancreatic rudiments from 14-day fetal rats were cultured whole for 8 days in medium containing 5·5 or 16·5 mmol glucose/l (1G or 3G medium). Rudiments grown in 3G medium (3G cells) contained more DNA and insulin than those grown in 1G medium (1G cells) but there was no alteration in the insulin/DNA ratio or the fractional area of the rudiment occupied by insulin-containing cells. Morphometric analysis of ultrastructure revealed that the β cells grown in 3G medium were smaller and had smaller nuclei than those grown in 1G medium. The size of exocrine cell nuclei in 1G or 3G medium was similar. Insulin granules occupied a greater proportion of the cytoplasmic volume in rudiments grown in 3G medium although the mean absolute volume of insulin granules per cell grown in 1G and 3G media was similar. Hence the residual cytoplasmic volume (cell—nucleus and granules) of 3G cells was less than that of 1G cells. Insulin granules from 3G cells had smaller granule sacs and cores than those from 1G cells. It is concluded that glucose stimulates the growth of rat fetal pancreas in vitro and has important effects on β cell ultrastructure.
J. Endocr. (1984) 100, 155–160
Sexual dimorphism involving steroidal pheromones and their binding protein in the submaxillary salivary gland of the Göttingen miniature pig
Authors: Booth W. D. 
Published: December 2008

ABSTRACT
Submaxillary glands of mature Göttingen miniature pigs were examined for the presence of a sexual dimorphism. Gland weights, serous cell hypertrophy and total protein in the glands were much greater in male than female pigs. High concentrations of the pheromonal 16-androstene steroids were present in the glands of males and exceeded 2 mmol/g in some animals; this was primarily due to 5α-androst-16-en-3α-ol. The high concentration of 16-androstene steroids in boar glands was correlated with the presence of large amounts of binding protein for these steroids in the glands; smaller amounts of the binding protein were detected in female glands. These findings are similar to those found in domestic pigs, but the degree of sexual dimorphism assessed from these findings is more extreme in the miniature pig.
J. Endocr. (1984) 100, 195-202
Neonatal glucocorticoid administration: effect on the diurnal rhythm of serum concentrations of corticosterone, progesterone and LH, and the response to pregnant mare serum gonadotrophin in immature female rats
Authors: Mann D. R. , Braverman M. , Cohen I. , Cost M. 
Published: December 2008

ABSTRACT
The effects of neonatal cortisol acetate administration on diurnal changes in serum corticosterone, progesterone and LH and on the response to pregnant mare serum gonadotrophin (PMSG) were examined in immature female rats. Neonatal cortisol treatment (250 μg/rat) abolished the diurnal rhythm of serum progesterone in rats at 27—29 days of age, and lowered overall the serum progesterone response to PMSG. Neonatal cortisol also reduced the number of animals ovulating on day 28 after PMSG injection 48 h earlier. This dosage of cortisol did not alter the diurnal rhythm of serum corticosterone in these animals. Serum LH concentrations in control rats at 27–29 days of age did not differ between 09.00 and 18.00 h, and prior treatment with cortisol acetate did not significantly influence serum concentrations of this hormone. Our data suggest that ovarian production of progesterone contributes significantly to diurnal fluctuations of this steroid in the circulation of immature rats. Perinatal exposure to cortisol acetate abolishes the diurnal rhythm of serum progesterone and impairs the ovarian response of the immature female rat to PMSG. The mechanism(s) by which cortisol acetate alters these processes remains to be determined.
J. Endocr. (1984) 100, 203–207
Ovarian steroid concentrations in rats approaching first ovulation
Authors: Toorop A. I. , Meijs-Roelofs H. M. A. , Kramer P. , de Greef W. J. 
Published: December 2008

ABSTRACT
Steroid concentrations were studied in ovarian tissue obtained by means of unilateral ovariectomy during a 10-day period preceding first ovulation. Furthermore, the levels of progesterone were measured in this period in the serum of simultaneous intact control rats.
Ovarian concentrations of testosterone and oestradiol were at about 70 and 15 fmol/mg ovary respectively from 10 to 4 days before first ovulation; they clearly increased to a maximum of 170 and 120 fmol/mg ovary during the last 1–3 days before first ovulation. Ovarian concentrations of 5α-reduced androgens (i.e. androsterone and 5α-androstane-3α, 17β-diol) were high (up to 2500 fmol/mg ovary) from 7 to 4 days before first ovulation, whereas low levels (500–750 fmol/mg ovary) were present during the last 3 days before ovulation. Both ovarian and serum concentrations of progesterone were constantly low (at 500–1000 fmol/mg ovary and at 17–32 nmol/l respectively) from 10 days to 1 day before first ovulation.
An inverse correlation was observed between the ovarian content of 5α-reduced androgens and that of oestradiol, which is in agreement with the existence of a prepubertal shift in pathways of steroid production; this shift seems to take place between 4 and 3 days before first ovulation.
Changes in ovarian steroids on the day of the first pro-oestrus were fully comparable to those at pro-oestrus in adults: relatively high levels of ovarian testosterone and oestradiol, reaching values of 339 and 711 fmol/mg ovary respectively during the morning, an increase in progesterone (from 986 to > 40 000 fmol/mg ovary) first observed at 14.00 h and a decline, observed at 17.00 h, in ovarian testosterone and oestradiol concentration, resulting in values of 9 and 3 fmol/mg ovary respectively at 21.00 h.
J. Endocr. (1984) 100, 281–286
Effect of pinealectomy on the plasma concentrations of prolactin, cortisol and testosterone in sheep in short and skeleton long photoperiods
Authors: Brinklow B. R. , Forbes J. M. 
Published: December 2008

ABSTRACT
Two experiments were carried out to investigate the effects of pinealectomy on the responses of prolactin, cortisol and testosterone to skeleton long photoperiods (7 h light: 10 h darkness: 1 h light: 6 h darkness; 7L: 10D: 1L: 6D) compared with short photoperiods (8L: 16D) in lambs. The first experiment included 23 female Suffolk cross sheep aged 10 months, of which six were pinealectomized. The skeleton long photoperiod significantly increased plasma levels of prolactin but this was blocked by pinealectomy; there was a peak around dusk and a trough around dawn and at the time of the 1-h period of light. There was no effect of either photoperiod or pinealectomy on plasma levels of cortisol. Testosterone was not measured in this experiment.
In the second experiment there were 12 intact males and 11 castrated males aged 3 months; six of the lambs in each group were pinealectomized. Prolactin was again greatly stimulated by skeleton long photoperiods and the effect was blocked by pinealectomy; there was a trough in plasma prolactin at dawn in all groups. In addition, castration increased prolactin levels on two of the four sampling days. Plasma cortisol concentrations were significantly lower under skeleton long photoperiods and this was also blocked by pinealectomy; there was no effect of castration. Testosterone was much higher in intact males. After 10 weeks of exposure, skeleton long photoperiods produced significantly lower concentrations than short photoperiods in the intact ram with pineal glands but not in those which were pinealectomized.
J. Endocr. (1984) 100, 287–294
Effects of stress administered during pregnancy on reproductive capacity and subsequent development of the offspring of rats: prolonged effects on the litters of a second pregnancy
Authors: Pollard I. 
Published: December 2008

ABSTRACT
The effects of high-anxiety-producing stress administered to rats during pregnancy were studied. The birthweight of offspring of both sexes from the stressed group was found to be significantly lower compared to birthweights of rats from unstressed mothers. The subsequent growth rates, however, were not affected. Mortality rate was significantly higher in the stressed group, although litter size, gestation length and sex ratios were not affected. Mean plasma resting corticosterone levels of the young pups did not differ between the two groups although they rose significantly as they aged in all groups. The offspring of both sexes from stressed mothers responded differently from the controls when subjected to short-term stress (one session) in adulthood. Their increase in plasma corticosterone concentration was significantly below that of the controls. This difference in response was abolished with long-term stress (10 days) when the males, but not the females, had habituated to the stressor. The observed inability to respond adequately to a sudden environmental change suggests a defective emergency response.
Lingering effects due to stressing were also found. Male offspring of a second litter, conceived by the original mothers 8 weeks after the discontinuation of stress, had significantly lower birthweights than those of the controls. The subsequent growth rate of neither sex was affected nor was the response to short-term stress.
J. Endocr. (1984) 100, 301–306
Investigations of the significance of the crepuscular LH peak in the ovulatory cycle of the hen (Gallus domesticus)
Authors: Johnson P. A. , van Tienhoven A. 
Published: December 2008

ABSTRACT
The crepuscular (occurring at dusk) peak of LH was characterized and its functional significance in the ovulatory cycle of the hen, Gallus domesticus, examined. Serial blood sampling on the night before the first ovulation (C1) of the sequence was followed by normal ovulations in six out of eight hens whereas blood sampling before a second or third ovulation (C2 or C3) of the sequence resulted in blocked ovulations in six out of seven hens. The difference in incidence of blocked ovulations was significant (P<0·02). Associated with normal ovulations was a significant (P<0·05) crepuscular peak in plasma LH whereas in those hens in which ovulation was blocked, no rise in LH at onset of darkness was detected. Serial blood sampling of hens on a night when 'lights-off' was delayed revealed a significant (P<0·05) crepuscular peak of LH at the time when the lights usually went off, indicating that the rise in LH had the property of a daily rhythm. When a 'lights-off' signal was given 4 h early before a C1 ovulation, a crepuscular peak of LH was induced (P<0·05) and preovulatory rises of LH and progesterone were significantly advanced (P<0·005 and P<0·02 respectively) compared with control hens, although not by the entire 4-h interval. This indicated that the crepuscular LH peak could be induced by the lights-off signal. Injections of chicken LH (cLH) which simulated a premature crepuscular LH peak were not effective in advancing the preovulatory surges of LH or progesterone or the resulting ovulations. The preovulatory surge of LH was potentiated (P<0·05), however, after the cLH injections, compared with the control values, although the treatment had no effect on preovulatory progesterone values. From these results we conclude that the crepuscular peak of LH may be necessary to initiate preovulatory events, but is not sufficient to do so.
J. Endocr. (1984) 100, 307–313
Testicular hormones and intermale aggressive behaviour in the presence of a female rat
Authors: Taylor G. T. , Haller J. , Rupich R. , Weiss J. 
Published: December 2008

ABSTRACT
A hypothesis was examined that increased levels of available testicular hormones are responsible for the increased aggressiveness of males in the presence of a female. In the first of two experiments intact male rats were injected with the androgen antagonist flutamide before exposure to oestrous, dioestrous or no females. Consistent with the hypothesis, flutamide-injected males were less aggressive than the respective control males which had been injected with oil alone. Yet the antiandrogen did not fully block the increased aggressiveness between males exposed to an oestrous female. In experiment 2 the aggressive behaviours of male rats in the presence of an oestrous female were observed after castration and restoration therapy with different amounts of testosterone propionate (TP). Neither a physiological amount (200 μg) nor an unusually large amount (800 μg) of TP could adequately mimic the effects of a gonadally intact male exposed to a sexually receptive female. These data suggest that differences in androgens available to target tissues influence aggressiveness among males exposed to a female. However, there are other factors involved, presumably the chronic morphological–physiological–behavioural changes that are provoked by copulatory experience.
J. Endocr. (1984) 100, 315–321
Oestrogen dependence of lactate dehydrogenase and peroxidase in cell subpopulations of 7,12-dimethylbenz[α] anthracene-induced mammary tumours in the rat
Authors: Safa A. R. , Brightwell J. R. , Tseng M. T. 
Published: December 2008

ABSTRACT
Recent investigations of certain enzymes as markers for predicting the response of breast tumours to hormonal therapy have neglected the possible differential contribution of cell subpopulation(s) within a solid tumour to enzyme activity. In this investigation, lactate dehydrogenase (LDH) and peroxidase activities in density-defined cell subpopulations from autotransplanted 7,12-dimethylbenz[α]anthracene-induced mammary tumours were determined. The effects of ovariectomy and subsequent oestrogen administration on the activity of these enzymes were also examined. Five cell subpopulations (cell bands) were routinely obtained from each mammary tumour. The highest LDH activity was found in cell band 4. The highest level of peroxidase activity was found in cell band 5. These two cell bands with high levels of enzyme activity consisted mainly of poorly differentiated cells. After bilateral ovariectomy, a significant (P < 0·001) decrease in the level of LDH activity in cell bands 3, 4 and 5 was observed. The enzyme activity was reduced to 20, 2·1 and 12% of the preovariectomy levels respectively. Significant (P < 0·05) decreases between baseline and postovariectomy peroxidase values were evident in each cell band. In the presence of oestradiol-17β, significant increases in the LDH activity of band 4 (P < 0·001) and the peroxidase activity of band 5 (P < 0·05) were observed. Our data suggest that, given the existence of multiple cell types in hormone-responsive tumour tissue, the actual cell subpopulation(s) responsible for any enzyme response may be a more precise indicator of hormone dependence.
J. Endocr. (1984) 101, 21–26
Effect of tri-iodothyronine on normal human lymphocyte function
Authors: Weetman A. P. , McGregor A. M. , Ludgate M. , Hall R. 
Published: December 2008

ABSTRACT
The effect of excessive tri-iodothyronine (T3) in vivo was assessed using normal human lymphocytes. Cells from normal subjects were frozen in liquid nitrogen before and after oral administration of T3 for 1 week to permit a direct comparison under identical culture conditions. Within the group of individuals studied, some subjects did show changes in B or T cell function but hypertri-iodothyroninaemia produced no consistent effect for the whole group on circulating T cell subsets or T and B cell activation measured by short-term culture or stimulation of lymphocyte cultures with phytohaemagglutinin or pokeweed mitogen. Tri-iodothyronine supplementation of cultures in vitro did not affect pokeweed mitogen stimulation. These findings suggest that the immunological abnormalities in Graves' disease are not the result of increased circulating thyroid hormone levels and that remission following medical treatment is due to an immuno-suppressive effect of the drug rather than the restoration of euthyroidism.
J. Endocr. (1984) 101,81–86
Action of anti-progesterone monoclonal antibody in blocking pregnancy after postcoital administration in mice
Authors: Wang M.-Y. , Rider V. , Heap R. B. , Feinstein A. 
Published: December 2008

ABSTRACT
Anti-progesterone monoclonal antibody injected intraperitoneally as a single dose 32 h post coitum completely blocked pregnancy in BALB/c and CBA nulliparous mice. The dose required was greater in CBA than in BALB/c females, but in both strains no implantation sites were detectable at autopsy on day 10 after mating. The action of the antibody in BALB/c females was associated with a failure to initiate an implantation response as indicated by the Pontamine Blue reaction. The most pronounced effect, however, was an arrest of embryonic development at a stage prior to cavitation. Plasma progesterone concentration in blood taken by cardiac puncture was greatly increased after treatment, by virtue of high-affinity binding by antibody in circulation. The results show that passive immunization against progesterone shortly after mating interferes with early hormone-dependent steps which are essential for normal embryonic development.
J. Endocr. (1984) 101, 95–100