bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF ANDROGENS, OESTROGENS AND DEOXYCORTICOSTERONE ACETATE ON PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE IN LAYING HENS
Authors: WILSON SUSAN C. , SHARP P. J. 
Published: December 2008

SUMMARY
Testosterone, androstenedione, oestrone, oestradiol-17β or deoxycorticosterone acetate (DOCA) were injected intramuscularly at several dose-levels and at various stages of the ovulatory cycle, and subsequent changes in plasma LH concentration were measured by radioimmunoassay.
In 19 out of 24 hens, injection of 0·1, 0·5 or 1·0 mg DOCA/kg resulted in a mean maximal increase in plasma LH concentration of between 0·47 and 2·10 ng/ml. The magnitude of this response was not related to either the dose or the stage of the cycle at which the DOCA was injected. In the remaining five hens DOCA failed to stimulate LH secretion. Injection of either androstenedione, oestrone or oestradiol did not result in any increase in LH level in the circulation. In contrast, injection of 0·5, 1·0 or 2·0 mg testosterone/kg between 22 and 26 h after the terminal ovulation of a sequence resulted in mean maximal incremental changes in plasma LH level of 1·98 ± 0·17, 2·17 ± 0·21 and 2·41 ± 0·31 (s.e.m.) ng/ml from pre-injection values of 1·38 ± 0·16, 1·58 ± 0·30 and 1·43 ± 0·39 ng/ml (n = 7, 6 and 5, respectively). The interval between the injection and the resulting rise in LH level was inversely proportional to the dose. The same doses of testosterone injected between 0 and 8 h after ovulation failed to stimulate LH secretion. There was also no significant increase in LH levels after injection of 0·5 and 1·0 mg testosterone/kg between 8 and 9 h after ovulation. However, injection of 2 mg testosterone/kg at this time resulted in a small but significant (P < 0·05) increase in LH levels.
Since the largest ovarian follicle is more mature at 22–26 h after ovulation than at 0–9 h after ovulation, the ability of testosterone to cause the release of LH therefore appears to depend upon the degree of maturation of the ovarian follicle next due to ovulate.
OESTRIOL, OESTRADIOL-17β AND THE PROLIFERATION AND DEATH OF UTERINE CELLS
Authors: MARTIN L. , POLLARD J. W. , FAGG BARBARA 
Published: December 2008

SUMMARY
It has been suggested that oestriol protects against breast cancer, because in some experiments on uterine growth it is only weakly active, and partially inhibits the effects of oestradiol-17β. When its effects are measured 24 h after a single injection, oestriol behaves as a typical impeded oestrogen with low potency and a flat dose-response line. This does net result from failure to stimulate certain critical stages of growth but from failure to sustain the products of growth. We found that oestriol induced all phases of uterine growth including DNA synthesis and cell division. It was as effective as oestradiol in stimulating early increases in protein synthesis and uterine weight, and half as effective in stimulating epithelial cells to replicate DNA and divide. However, epithelial cell numbers did not increase after a single injection of oestriol because cell death rate increased at the same time as mitotic rate, apparently as a result of the more rapid loss of oestriol from the uterus.
Repeated injections of oestriol prevented premature cell death and produced as much uterine hypertrophy and hyperplasia as oestradiol-17β. These results support the thesis that the oestrogenic potency of a substance is largely determined by the duration of its occupation of receptors. Thus in situations of continuous production, (e.g. pregnancy) oestriol would be as active as oestradiol and unlikely to exert any significant 'buffering' or protective action.
The findings are also discussed in relation to a new model for the regulation of cell proliferation.
EXPERIMENTAL DIABETES INSIPIDUS IN A MARSUPIAL, MACROPUS EUGENII (DESMAREST)
Authors: BAKKER H. R. , WARING H. 
Published: December 2008

SUMMARY
A new method is described for placing lesions in the supraoptico-neurohypophysial tract to produce diabetes insipidus. The method is particularly useful with species such as Macropus eugenii in which different individuals show a large variation in relative skull measurements.
The development of the diabetes insipidus syndrome in the tammar wallaby (Macropus eugenii) is shown to have essentially the same triphasic pattern of urine production as in eutherians.
Increased values of adrenal corticosteroids (> 16 μg/100 ml plasma) were observed in the oliguric interphase. This has not been previously reported and we suggest that these increased values are most probably due to potentiation of corticotrophic releasing factor by the uncontrolled release of vasopressin during this phase.
EFFECTS OF POSTNATAL THYROXINE ADMINISTRATION ON BRAIN DEVELOPMENT, RESPONSE TO POSTNATAL ANDROGEN AND THYROID REGULATION IN FEMALE RATS
Authors: PHELPS C. P. , LEATHEM J. H. 
Published: December 2008

SUMMARY
Some developmental and functional manifestations of thyroxine (T4) administered on the first 2 days of postnatal life were studied in the female rat. Brain myelinogenesis estimated by brain esterified cholesterol concentration, and brain myelin age estimated by brain total cholesterol concentration, were subsequently determined. Thyroxine treatment resulted in a greater concentration of esterified cholesterol in the brain than saline treatment, but the latter appeared to delay the normal increase shown by non-injected controls. Thyroxine treatment resulted in total and free cholesterol levels similar to those of non-injected controls, these again being greater than those in saline-treated rats. Cholesterol concentrations in liver and serum were not affected by T4 or saline treatment.
Administration of T4 to female rats before administration of 1·25 mg testosterone propionate on day 7 resulted in an ovarian and uterine weight response to human chorionic gonadotrophin (HCG, 1 i.u./day on days 23–26) on day 27 that was greater than that in litter-mates given saline at birth before testosterone propionate and HCG treatment. Postnatal T4 treatment alone in the female was also associated with a reduced thyroid and pituitary gland enlargement after 7 days of propylthiouracil feeding (0·015% in tap water, days 24–31 of life) when compared with either saline or non-injected controls.
EFFECTS OF SEXUAL ACTIVITY ON LUTEINIZING HORMONE AND TESTOSTERONE LEVELS IN THE ADULT MALE RABBIT
Authors: YOUNGLAI E. V. , MOOR B. C. , DIMOND P. 
Published: December 2008

SUMMARY
Sexually mature New Zealand White male rabbits were subjected to various sexual stimulation procedures. Plasma samples were obtained through an indwelling catheter in the central ear artery and analysed for LH and testosterone using specific radioimmunoassays. Coitus and exposure to females occasionally led to increases in testosterone levels which were usually preceded by a rise in LH. Increases in hormone concentration were not significantly different from those of rabbits which did not mate or which were isolated from females. These results suggest that coitus in the male rabbit does not cause the massive increase in LH concentration which is known to occur in the female.
PLASMA LUTEINIZING HORMONE AND PROGESTERONE IN THE ADULT FEMALE PIG DURING THE OESTROUS CYCLE, LATE PREGNANCY AND LACTATION, AND AFTER OVARIECTOMY AND PENTOBARBITONE TREATMENT
Authors: PARVIZI N. , ELSAESSER F. , SMIDT D. , ELLENDORFF F. 
Published: December 2008

SUMMARY
In a series of experiments on female miniature pigs, the pattern of plasma LH and progesterone levels during the oestrous cycle, late pregnancy and lactation and after ovariectomy were characterized, and the effect of pentobarbitone treatment was tested.
The preovulatory surge of LH occurred in seven out of eight animals between 00.00 and 12.00 h on day 0 of the oestrous cycle (day 1 of standing heat). Plasma progesterone started to decline 8 days before oestrus and reached its lowest value 5 days before the preovulatory LH peak. Increases in progesterone concentration were already noticeable 48 h after the LH surge. During late pregnancy, parturition and lactation, plasma LH was low and showed only minor fluctuations, while plasma progesterone declined 4 to 5 days before parturition. Both hormones remained at low levels throughout lactation. Three weeks before parturition increases in LH were always followed by an increase in progesterone. This dependency was greatly diminished immediately before delivery. Four to 12 days after weaning the animals came into oestrus which was followed by an increase in LH and later an increase in progesterone concentrations.
Ovariectomy during dioestrus resulted in a steady increase in plasma LH levels for 35–39 days. Ovariectomy caused abortion if performed on day 100 of pregnancy. It was followed by a rapid increase of plasma LH concentration. Normal parturition (around day 115) and lactation took place when animals were spayed on day 112 of pregnancy. In this case, plasma LH levels remained even lower than before ovariectomy as long as lactation was maintained. Immediately after weaning a rapid increase in the normal postovariectomy pattern of LH secretion was observed.
Pentobarbitone anaesthesia (30–35 mg/kg body wt, initial dose), during pro-oestrus– oestrus, for less than 5 h had no effect on the preovulatory LH increase. However, pentobarbitone anaesthesia for more than 6 h inhibited the LH peak and ovulation if the animal was under deep anaesthesia before 24.00 h on the day before oestrus. Pentobarbitone treatment of ovariectomized pigs resulted in a clear decrease in LH levels 40 min after a single i.v. dose.
ACTIVITY OF STEROID C-17,20 LYASE IN THE OVINE PLACENTA: EFFECT OF EXPOSURE TO FOETAL GLUCOCORTICOID
Authors: STEELE PENELOPE A. , FLINT A. P. F. , TURNBULL A. C. 
Published: December 2008

SUMMARY
Microsomal fractions isolated from post-partum ovine placentae catalysed the synthesis of [3H]oestrone and [3H]oestradiol from [3H]17α-hydroxyprogesterone and NADPH; oestrone and oestradiol were formed in a ratio of approximately 50:1. The expected intermediate, [3H]androstenedione, did not accumulate during these incubations but was shown by trapping experiments to be the intermediate involved. Mean ( ± s.d.) yields of [3H]oestrone (% conversion of substrate) during incubation for 1 h of placentae from five animals in late pregnancy before the onset of labour, from five animals which delivered spontaneously at term and from four animals in which labour was induced by administration of dexamethasone to the foetus were: in tissue obtained before labour, 3·2 ± 0·44; in tissue obtained after the spontaneous onset of labour, 20·6 ± 10·2 (P < 0·01) and in tissue obtained after dexamethasone-induced labour, 24·4 ± 2·13 (P < 0·001). This increase in oestrone synthesis suggests activation of steroid C-17,20 lyase, since this is the step limiting the rate of synthesis of oestrone in vitro. The enzyme is probably activated by foetal glucocorticoid. The findings are discussed in relation to the site of synthesis of oestrogens which in the sheep increase in concentration in the peripheral circulation at term, and with reference to a possible mechanism by which foetal glucocorticoid may control the onset of labour in this species.
EFFECTS OF FERROUS IONS ON PREOPTIC AREA NEURONES AND LUTEINIZING HORMONE SECRETION IN THE RAT
Authors: DYER R. G. , BURNET F. 
Published: December 2008

SUMMARY
Ferrous ions (Fe2+) were applied by microiontophoresis to 29 neurones recorded from the forebrain of ten pro-oestrous rats. The spontaneous activity of 24 cells was reduced by Fe2+ and five units did not respond. No excitations were observed. Reproducible responses could not be obtained with ferric ions (Fe3+).
Microinjection of 1 μl 200 mm-Fe2+ into the preoptic area of eight pro-oestrous rats produced a sharp increase in plasma LH levels. Similar treatment with saline was without effect. Rats anaesthetized with sodium pentobarbitone during the early afternoon of pro-oestrus ovulated overnight when injected with both Fe2+ and Fe3+.
The experiments do not confirm the widely held belief that raised plasma LH levels following deposition of iron in the rostral hypothalamus result from increased firing of nerve cells.
PURIFICATION AND PROPERTIES OF THE SUBUNITS OF HUMAN PITUITARY FOLLICLE-STIMULATING HORMONE
Authors: SHOWNKEEN RATNA C. , HARTREE ANNE STOCKELL , STEWART FRANCESCA , MASHITER K. , STEVENS V. C. 
Published: December 2008

SUMMARY
Highly purified human pituitary FSH was partially dissociated by treatment with 8 m-urea, and α- and β-subunits were isolated by ion-exchange chromatography and gel filtration. Tests of biological activity by in-vivo assays and in-vitro radioreceptor assays were in good agreement and showed that preparations of isolated α-subunit had less than 1%, and β-subunit from 2 to 10% of the FSH activity of the intact hormone. In contrast to results reported elsewhere, most of the subunit preparations reassociated with counterpart subunit to regain biological activity equal to that of intact FSH (around 160 mg NIH-FSH-S1/mg). The intact FSH recovered as a by-product after isolation of subunits was of high biological activity, and its LH contamination was reduced by more than 90% when compared with the purified FSH starting material. The subunits are relatively inactive in a radioimmunoassay specific for intact FSH. Sialic acid and tryptophan determinations indicated that both subunits contain sialic acid and that tryptophan is present only in the β-subunit.
PRIMING EFFECT OF LUTEINIZING HORMONE RELEASING FACTOR: IN-VITRO AND IN-VIVO EVIDENCE CONSISTENT WITH ITS DEPENDENCE UPON PROTEIN AND RNA SYNTHESIS
Authors: PICKERING A. J. M. C. , FINK G. 
Published: December 2008

SUMMARY
The aim of this study was to determine whether the priming effect of LH-RF depends upon RNA and protein synthesis. In in-vivo studies saline, actinomycin D, or cycloheximide was administered i.p. 3·5–4 h before the first i.v. injection of synthetic LH-RF into pro-oestrous rats anaesthetized with sodium pentobarbitone at 13.30 h. The LH-response to the second injection of LH-RF (given 60 min after the first) was markedly reduced by the inhibitors, but the response to the first injection was not significantly affected. Studies with cycloheximide given i.v. showed that the inhibition of protein synthesis up to the second injection of LH-RF reduced the magnitude of the priming effect, the reduction being greatest when the inhibitor was administered up to 30 min after the first LH-RF injection. Pituitary incubation studies showed that the priming effect could also be elicited in vitro and that it could be significantly reduced by actinomycin D, cycloheximide and puromycin. As in vivo, the inhibitors had relatively little effect on the LH-response to the first exposure to LH-RF. The protein synthesized after an injection of LH-RF may be new LH, and/or a protein(s) concerned with 'activation' of the receptor or release components of the LH-secretory apparatus.
STEROIDOGENIC PATHWAYS AND TROPHIC RESPONSE TO ADRENOCORTICOTROPHIN OF CULTURED ADRENOCORTICAL CELLS IN DIFFERENT STATES OF DIFFERENTIATION
Authors: SLAVINSKI E. A. , JULL J. W. , AUERSPERG N. 
Published: December 2008

SUMMARY
Adrenocortical cells obtained from adult rats were propagated in monolayer culture. Depending on culture conditions, they grew either as lipid-containing epithelial-like cells with a high level of steroid production, or as fibroblast-like cells with a low level of steroid production. The major fluorogenic steroid secreted by both morphologic forms of adrenal cortical cell was corticosterone as determined by chromatography and acid fluorometry. Basal fluorogenic steroid production per 106 cells over 24 h was: epithelial-like cells, 5·0 μg; fibroblast-like cells, 0·014 μg. Stimulation with ACTH for 5 days increased fluorogenic steroid production and induced morphologic changes in both adrenal cell forms. ACTH stimulation of fluorogenic steroid production by both cell forms reached a maximum after 3 days, then dropped to a refractory state after 5 days. With maximal ACTH stimulation, production increased 25-fold in fibroblast-like cells and five-fold in epithelial-like cells. The latter rate of corticosterone production is similar, per cell, to ACTH-stimulated adrenal glands in vivo. Progressive morphologic changes were observed with ACTH stimulation: epithelial-like cells retracted from the substratum and lost lipid inclusions; fibroblast-like cells became more epithelial-like. Both adrenal cell types formed intermediates from [4-14C]pregnenolone including pregn-5-ene-3β,20α-diol and 20α-hydroxypregn-4-en-3-one. Control cultures of muscle fascia fibroblasts did not produce corticosterone or intermediates from [4-14C]pregnenolone and did not respond to ACTH functionally or morphologically.
STUDIES ON THE UPTAKE AND BINDING OF 5α-ANDROSTANE-3α,17α-DIOL BY CANINE PROSTATIC NUCLEI
Authors: EVANS C. R. , PIERREPOINT C. G. 
Published: December 2008

SUMMARY
Nuclei have been isolated from canine prostatic tissue previously incubated with tritiated testosterone or tritiated 5α-androstane-3α,17α-diol. The protein-bound radioactivity has, in both cases, been shown to be associated with 5α-androstane-3α,17α-diol. The formation and translocation of this steroid to the nucleus supports previous evidence that it has an active part to play in prostatic function in the dog. The formation from testosterone of another tritiated steroid, possibly 5α-dihydrotestosterone, was also demonstrated although this product did not enter the nucleus and was apparently bound to the nuclear membrane.
DIOESTROUS PROGESTERONE AND PRO-OESTROUS LUTEINIZING HORMONE IN 4- AND 5-DAY CYCLES OF FEMALE RATS
Authors: VAN DER SCHOOT P. , DE GREEF W. J. 
Published: December 2008

SUMMARY
Female rats which showed 5-day ovarian cycles spontaneously, but 4-day cycles for periods of variable length after induction of pseudopregnancy, were examined. While the time of onset of the ovulatory LH surge at pro-oestrus was the same in both 4- and 5-day cycles, dioestrous progesterone concentrations were dissimilar. The most prominent feature was a sharp increase during the night of the first day of dioestrus of the 4-day cycles. The results are interpreted as suggesting that dioestrous steroid concentrations rather than pro-oestrous LH concentrations are important in establishing cycle duration.
ENDOCRINE AND ENVIRONMENTAL INFLUENCES UPON PLASMA CORTISOL CONCENTRATIONS AND PLASMA RENIN ACTIVITY OF THE EEL, ANGUILLA ANGUILLA L.
Authors: HENDERSON I. W. , JOTISANKASA VARUNEE , MOSLEY W. , OGURI M. 
Published: December 2008

SUMMARY
The plasma concentrations of cortisol, sodium, potassium and calcium and plasma osmolarity were determined in freshwater silver eels, after intravascular injections of eel renin preparations, mammalian ACTH, mammalian angiotensin II and eel muscle extracts. Arterial blood specimens were taken before and after injection of test substances. Partially purified eel and rat renal renins gave prolonged pressor responses in intact and hypophysectomized eels and in the nephrectomized rat anaesthetized with sodium pentobarbitone.
Angiotensin, but not ACTH, produced obvious pressor responses in intact and hypophysectomized eels and in eels without their corpuscles of Stannius. Hypophysectomized eels 4–8 days after operation had reduced plasma cortisol concentrations. No change in cortisol occurred in eels after removal of the corpuscles of Stannius. Eel renin preparations and ACTH gave increased concentrations of plasma cortisol 30 min after injection into hypophysectomized and intact eels. In general, the length of the renin-generated pressor response and the increased cortisol concentration were concomitant occurrences.
Angiotensin injected into eels with corpuscles of Stannius removed and into hypophysectomized eels also increased cortisol levels. Control muscle extracts produced no significant changes. There were no acute changes in plasma electrolyte concentrations after the injections.
Plasma renin activity measured indirectly by bioassay of angiotensin generated in vitro was more than twice as great in eels adapted to seawater than in eels in fresh water. Plasma renin activity gradually fell when eels were transferred from seawater to fresh water, and increased when the reverse transfer was carried out.
SITE OF ORIGIN OF THE PULSATILE SECRETION OF LUTEINIZING HORMONE IN LONG-TERM OVARIECTOMIZED RATS
Authors: SCHUILING G. A. , GNODDE H. P. 
Published: December 2008

SUMMARY
If long-term ovariectomized rats are treated with the long-acting barbiturate, sodium phenobarbitone, the well-known pulsatile secretion of LH is depressed, resulting in a constant, still raised, plasma LH level. This indicates that in all probability ovariectomized rats secrete LH in both a tonic and a pulsatile way, only the latter being sensitive to phenobarbitone treatment.
Constant infusions of synthetic LH-RH into phenobarbitone-treated ovariectomized rats induced a steadily increasing plasma LH concentration without pulsations, whereas pulsatile infusions of the releasing hormone, following a constant infusion, resulted in a pulsatile secretion of LH. This indicates that the pulsatile secretion of LH in ovariectomized rats is the result of a pulsatile secretion of the hypothalamic releasing hormone; the pituitary gland itself is not the site of origin of the phenomenon.
CORTICOSTEROID PRODUCTION BY THE HUMAN FOETUS: EVIDENCE FROM ANALYSIS OF URINE FROM WOMEN PREGNANT WITH A NORMAL OR AN ANENCEPHALIC FOETUS
Authors: CAWOOD MARION L. , HEYS R. F. , OAKEY R. E. 
Published: December 2008

SUMMARY
The quantities of nine corticosteroids in 24 h urine samples collected by pregnant women (nine with normal foetuses and nine with anencephalic foetuses) were measured after hydrolysis with β-glucuronidase and separation by paper chromatography. The excretion (μmol/24 h, mean ± s.d.) of pregnanetriol (0·85 ± 0·17), 3α,17α-dihydroxy-5β-pregnan-20-one 17α-hydroxypregnanolone, 0·55 ± 0·17), 3α,17α,21-trihydroxy-5β-pregnan-20-one (tetrahydro-11-deoxycortisol, 0·17 ± 0·14) and tetrahydrocorticosterone (0·65 ± 0·26) by women with an anencephalic foetus was significantly lower (P < 0·01 or <0·05) than the excretion of these compounds by women with a normal foetus (pregnanetriol, 2·42 ± 0·62; 17α-hydroxypregnanolone, 2·72 ± 0·69; tetrahydro-11-deoxycortisol, 0·56 ± 0·37; tetrahydrocorticosterone, 1·95 ± 0·94). These differences suggest that the adrenal of the normal foetus contributes to the quantity of pregnanetriol, 17α-hydroxypregnanolone, tetrahydro-11-deoxycortisol and tetrahydrocorticosterone in maternal urine. The excretion of tetrahydrocortisol, tetrahydrocortisone, tetrahydrodeoxycorticosterone, cortol and cortolone were similar in both groups of subjects.
No evidence was obtained therefore to indicate the secretion of cortisol or deoxycorticosterone by the foetal zone of the adrenal of the undisturbed human foetus in late gestation.
ABNORMAL LUTEINIZING HORMONE RESPONSE PATTERNS TO SYNTHETIC GONADOTROPHIN RELEASING HORMONE IN PATIENTS WITH POLYCYSTIC OVARIAN SYNDROME
Authors: KATZ M. , CARR P. J. 
Published: December 2008

SUMMARY
Basal gonadotrophin and sex steroid levels and responses to an intravenous injection of 100 μg gonadotrophin releasing hormone (Gn-RH) have been studied in 15 patients with polycystic ovaries. Mean basal LH concentration was raised and an excessive, exaggerated and prolonged response was observed after Gn-RH treatment, but patients could further be subdivided into two functional groups on the basis of their basal LH values and LH response patterns. Evidence was also produced which suggested a breakdown in the negative feedback mechanism in these patients.