bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF ANDROGEN ON THE AVERSIVE PROPERTIES OF MALE MOUSE URINE
Authors: JONES R. B. , NOWELL N. W. 
Published: December 2008

SUMMARY
The aversive properties of urine of castrated male mice receiving varying doses of testosterone phenylpropionate was assayed using males housed in groups of six as subjects. The aversive efficacy of the urine was found to rise with an increase in androgen levels. There was a delay of 5 days before the exogenous androgen exerted any effect on the aversive properties of the urine. This delay indicated that the aversive factor might be a pheromonal substance released from an androgen-dependent tissue, rather than being an excreted androgen metabolite.
The results are discussed in terms of androgen levels and possible territorial functions.
THE 11-OXYGENATION INDEX IN PREGNANCY: TENTATIVE EVIDENCE FOR DECREASED FOETAL ADRENOCORTICAL ENZYME ACTIVITY AT PARTURITION
Authors: MAKIN H. L. J. , TRAFFORD D. J. H. , WARD PATRICIA R. , LANE J. 
Published: December 2008

SUMMARY
The urinary 11-oxygenation index has been measured throughout pregnancy in 25 women. The index rose steadily throughout pregnancy. At about 35 weeks gestation it rose rapidly, reached a peak just before parturition and rapidly fell to normal thereafter. Statistical analysis indicated that there might be differences in the index levels between women who delivered spontaneously and women in whom induction was necessary. It is suggested that this rise in the index reflects a foetal adrenocortical enzyme inactivity, leading to an increased secretion of cortisol precursors into the maternal circulation at term, which may be involved in the processes of parturition.
SINGLE UNIT ACTIVITY IN THE HYPOTHALAMO-NEUROHYPOPHYSIAL SYSTEM OF BRATTLEBORO RATS
Authors: DYBALL R. E. J. 
Published: December 2008

SUMMARY
Unit activity was recorded in the supraoptic (SO) and paraventricular (PV) nuclei in Brattleboro (DI) rats both homozygous and heterozygous for the factor causing diabetes insipidus, and from normal Long-Evans rats from which the Brattleboro strain is derived. In these nuclei the distance between cells which could be antidromically excited by stimulation of the neural lobe did not differ between the three groups of animals. The electrical properties of the antidromically excited neurones, as judged by the latency of the antidromic spike, the maintenance of the amplitude of the spikes after short trains of stimuli, the existence of phasically firing units and antidromic inhibition, did not seem impaired in DI rats. The spontaneous discharge rates of antidromically identified neurones in the SO nuclei of both homozygous and heterozygous DI rats, but not of other hypothalamic units, were significantly faster than those in normal animals. Plasma sodium concentration and osmolality are known to be higher than normal in homozygous but not in heterozygous DI rats. These are therefore unlikely to be the only factors responsible for the increased firing rates in the SO nucleus of DI rats. The results are consistent with the suggestion that the primary lesion in DI rats is an impairment of vasopressin biosynthesis which does not involve the electrical properties of the neurones.
RELATIONSHIP OF VISCERAL BLOOD FLOW TO CORTISOL METABOLISM IN COLD-STRESSED SHEEP
Authors: PANARETTO B. A. 
Published: December 2008

SUMMARY
Whole body metabolic clearance rates (MCR) and splanchnic, hepatic and renal clearance rates of cortisol were estimated in six shorn sheep under control conditions. The measurements were repeated in the same animals when they were exposed to a cold, wet environment while they were maintaining a normal rectal temperature and again when they became hypothermic, their mean final rectal temperature ( ~ 36 °C) having been reduced approximately 2–3 °C below the control range. The quantitative changes in MCR that occurred during cold stress were found to be associated with corresponding changes in splanchnic and renal clearance rates. Increases in plasma cortisol concentrations up to 50 μg/1 were accompanied by proportional increases in rates of splanchnic blood flow and cortisol clearance. When cortisol concentrations rose above 50 μg/1 in hypothermic animals the MCR values tended to fall because of reductions in hepatic and renal blood flow; very large increases in plasma cortisol concentrations then resulted from comparatively small increases in production rate.
CHANGES IN PLASMA LEVELS OF OESTRADIOL, PROGESTERONE AND LUTEINIZING HORMONE IN IMMATURE RATS TREATED WITH PREGNANT MARE SERUM GONADOTROPHIN
Authors: WILSON CATHERINE A. , HORTH C. E. , ENDERSBY C. A. , McDONALD P. G. 
Published: December 2008

SUMMARY
The pattern of hormonal changes just before ovulation was investigated in immature rats induced to ovulate with pregnant mare serum gonadotrophin (PMSG). Oestradiol levels in the blood reached a maximum 42–52 h after PMSG treatment and then decreased dramatically. Pituitary luteinizing hormone (LH) levels remained constant until the time of the critical period (50–52 h) and then fell significantly. Plasma LH levels started to rise at 52 h, reached a peak at 54 h and fell to undetectable levels by 58 h. Plasma progesterone also reached a peak at 54 h and then fell slowly over the following dark period. The timing and pattern of changes in plasma and pituitary hormone levels were very similar to those seen in adult rats before ovulation. There was a positive correlation between the dose of PMSG, the peak concentration of plasma oestradiol and the average number of ova shed.
BLOOD AND URINE CLEARANCE OF LUTEINIZING HORMONE RELEASING HORMONE IN MAN MEASURED BY RADIOIMMUNOASSAY
Authors: JEFFCOATE S. L. , GREENWOOD R. H. , HOLLAND D. T. 
Published: December 2008

SUMMARY
The clearance of synthetic luteinizing hormone releasing hormone (LH-RH) after intravenous injection has been investigated in man. Thirteen tests were performed in ten subjects, four of whom were normal, the other six had proven disease of the hypothalamo-pituitary region. The rate of disappearance of LH-RH from the circulation could be represented as a double exponential with half-times of the two components of 5·3 and 27·4 min respectively. The initial volume of distribution was 11·1 ± 1·6 (s.d.) 1 and the metabolic clearance rate 1480 ± 170 (s.d.) 1/day. There was no difference in any of these parameters between normal and abnormal subjects. Between 0·75 and 2·8% of the injected dose was excreted in the urine within 8 h, of which 48% was excreted in the first hour. The daily production rates of LH-RH were calculated from the urinary excretion rates; these gave higher results than production rates calculated from the blood metabolic clearance rate. Possible reasons for this are discussed.
FAMILIAL GOITRE WITH ABSENCE OF THYROGLOBULIN AND SYNTHESIS OF THYROID HORMONES FROM THYROIDAL ALBUMIN
Authors: DESAI K. B. , MEHTA M. N. , PATEL M. C. , SHARMA S. M. , RAMANNA L. , GANATRA R. D. 
Published: December 2008

SUMMARY
Two siblings, a brother (H. B.) and a sister (R. B.) with long standing goitres were investigated. Radioactive iodine uptake by the thyroid was increased and a significant portion of the plasma radioactive iodine was not extractable with butanol. Chromatography of butanol extracts of serum after radioactive iodine administration showed distinct peaks of triiodothyronine and thyroxine. Microscopic examination of the surgical specimens of the goitres showed Hürthle cell carcinoma with follicles devoid of colloid in both specimens. Sucrose density gradient centrifugation, gel filtration on Sephadex G-200, salting out procedures, starch gel electrophoresis and immunological tests of the supernatant soluble fraction of thyroid homogenates showed a lack of thyroglobulin. Further fractionation of the soluble proteins showed that albumin was apparently involved in the synthesis of thyroid hormones in the absence of thyroglobulin.
FACTORS INFLUENCING THE UPTAKE OF [α-14C]AMINOISOBUTYRIC ACID BY RAT TESTES
Authors: IRUSTA O. , WASSERMANN G. F. 
Published: December 2008

SUMMARY
The action of various agents on the distribution ratio of [α-14C]aminoisobutyric acid ([14C]AIB) in the testes of adult and growing rats was studied. A decrease in the distribution ratio of [14C]AIB was observed in the testes during maturation. Follicle-stimulating hormone (FSH) administered in vivo to 22-day-old rats or to mature hypophysectomized animals increased the distribution ratio of [14C]AIB in testicular cells. Dibutyryl adenosine 3′: 5′-cyclic phosphate augmented the [14C]AIB uptake into testes of intact or hypophysectomized mature animals. This nucleotide was ineffective in rats under 32 days of age. Testes from mature and immature rats preincubated in vitro with cycloheximide for 1 h showed a decrease in the distribution ratio of [14C]AIB. Cycloheximide also blocked the action of FSH on [14C]AIB uptake in the testes of 22-day-old rats.
THE EFFECTS OF CALCITONIN AND PARATHORMONE ON PLASMA MAGNESIUM LEVELS BEFORE AND AFTER BIRTH IN THE RAT
Authors: GAREL J. M. , BARLET J. P. 
Published: December 2008

SUMMARY
Plasma magnesium levels measured in rats from 16·5 to 21·5 days of gestation and during the first week after birth proved to be invariably higher in the foetus than in the mother. The highest level observed was in the 16·5-day-old foetus. A small decrease occurred between 16·5 and 17·5 days of gestation; thereafter the plasma magnesium level did not change until 19·5 days and then decreased between 19·5 and 21·5 days. After birth an increase in plasma magnesium occurred with suckling but then remained constant during the first week of life.
Parathyroid hormone (0·25 USP unit/g) injected into 21·5-day-old foetuses had no effect on plasma magnesium levels from 0·5 to 24 h after injection. This dose was found to be very potent in raising plasma calcium values 4 h after injection. In the 3-day-old newborn rat this dose was similarly ineffective. Removal of the foetal parathyroid glands by decapitation at 17·5 days of gestation was followed by a decrease in plasma magnesium at 21·5 days of gestation. Parathyroid hormone (0·25 USP unit/g) injected into decapitated foetuses did not change the level of magnesium in the plasma.
Salmon calcitonin (S-CT) at two doses (0·4 and 4 ng/g) produced no effect on plasma magnesium concentrations in 3-day-old newborn rats 3 h after injection; whereas at both doses, marked diminutions in plasma calcium and phosphate concentrations were observed. After injection of 40 ng S-CT/g, plasma magnesium decreased in 3-day-old newborn rats 3 h after injection. This dose was found to decrease plasma magnesium in the 19·5-day-old foetus and in the 20·5-day-old foetus. Before 19·5 days of gestation no effect was observed.
BINDING OF LUTEINIZING HORMONE AND HUMAN CHORIONIC GONADOTROPHIN TO OVARIAN CELLS AND ACTIVATION OF ADENYLATE CYCLASE
Authors: KOCH Y. , ZOR U. , CHOBSIENG PRAKONG , LAMPRECHT S. A. , POMERANTZ S. , LINDNER H. R. 
Published: December 2008

SUMMARY
The binding of 125I-labelled ovine luteinizing hormone (OLH) and human chorionic gonadotrophin (HCG) to unbroken cells or homogenates from rat and bovine ovaries was studied in relation to the hormonal activation of adenylate cyclase. Both hormones are preferentially bound to ovarian tissue (luteal as well as follicular), while adrenal, kidney and liver showed no specific binding. The bound HCG was associated chiefly with the fraction of the homogenate sedimenting at 1000 g. Addition of excess unlabelled hormone (HCG, OLH) together with the corresponding or heterologous 125I-labelled hormone reduced the radioactivity bound to the tissue by 70–90%; rat LH also competed with OLH and HCG for binding sites, but follicle-stimulating hormone, prolactin, growth hormone, adrenocorticotrophin or glucagon were without effect. Binding could be dissociated from activation of adenylate cyclase by a two-stage incubation: at 4 °C rat ovarian slices bound the labelled hormones, though binding efficiency was reduced to about 20%, but no stimulation of the enzyme was observed. Reincubation of these slices, after washing, at 37 °C in hormone-free medium resulted in maximal activation of adenylate cyclase. Addition of homologous antibodies before the second incubation step abolished the effect of OLH but not that of HCG on the activation of the enzyme. Similarly, addition of homologous antibodies or of excess unlabelled hormone caused dissociation of bound 125I-labelled OLH but not of 125I-labelled HCG from receptor sites. It is concluded that (i) HCG, OLH and rat LH are bound to the same receptor on ovarian cells, but binding of OLH to the receptor is more labile than that of HCG; (ii) the receptor appears to be located on the plasma membrane, since it was largely associated with the 1000 g pellet and since bound OLH remained accessible to antibody; (iii) activation of adenylate cyclase requires the continued occupation of the binding site by the hormone, but occupation of only a fraction of the receptor sites by hormone is adequate to induce maximal production of cyclic AMP by the target tissue.
EFFECT OF SUCKLING AND ASSOCIATED FACTORS ON OVARIAN COMPENSATORY HYPERTROPHY DURING LACTATION IN THE RAT
Authors: MENA F. , AGUAYO D. , REYES G. , BEYER C. 
Published: December 2008

SUMMARY
The mechanism by which suckling affects the hypothalamo-pituitary-ovarian system was studied in lactating Wistar rats. Unilateral ovariectomy was carried out on day 4 post partum and the subsequent ovarian compensatory hypertrophy (OCH) was assessed on day 14 post partum. The weight of the corpora lutea (CL) of lactation, the CL of pregnancy and of the remainder of the ovary, here termed interstitial tissue, was determined for both ovaries. A clear OCH, mainly due to an increase in interstitial tissue, occurred in rats whose pups were removed on day 4 post partum. Suckling by two pups inhibited OCH, whereas suckling by six or ten pups produced significant ovarian atrophy, these effects being due to a decrease in weight of both interstitial tissue and CL of pregnancy which overcame an increase in weight of the CL of lactation. Inhibition of OCH occurred in spinal-cord transected rats suckling six pups. Suckling was suspended in unilaterally ovariectomized rats nursing ten pups on day 14 post partum, and the weight of the remaining ovary was determined 16, 32, 64 and 96 h later in four groups of rats. The weight of the remaining ovary returned to that of the control ovary 64 h after withdrawal of suckling. This effect was due to an increase in weight of interstitial tissue and of the CL of lactation. Maintenance of suckling for 64 h in rats with the galactophores ligated to prevent milk removal, inhibited OCH. By contrast, both oxytocin injections and exteroceptive stimulation provided by litters failed to block ovarian growth after suckling withdrawal. The results suggest that suckling itself is an important influence in the inhibition of OCH, but that other factors may contribute to the ovarian changes observed during lactation in the rat.
THE THYROTROPHIN RECEPTOR IN GUINEA-PIG THYROID HOMOGENATE: INTERACTION WITH THE LONG-ACTING THYROID STIMULATOR
Authors: MANLEY S. W. , BOURKE J. R. , HAWKER R. W. 
Published: December 2008

SUMMARY
Immunoglobulin G (IgG) prepared from sera containing the long-acting thyroid stimulator (LATS) inhibited the receptor binding of 125I-labelled thyrotrophin (TSH) in a particulate fraction of guinea-pig thyroid homogenate. This inhibition was shown to involve a binding interaction between IgG containing LATS and the receptor with a diminution in the number, but not affinity, of sites available for binding of TSH. Studies of dissociation kinetics and gel filtration of receptor—TSH complexes indicated that IgG containing LATS did not combine with receptors occupied by TSH. The data provide evidence that LATS and TSH bind to the same receptor site.
THE OVARIAN FOLLICLE OF THE SHEEPINHIBITION OF OESTROGEN SECRETION BY LUTEINIZING HORMONE
Authors: MOOR R. M. 
Published: December 2008

SUMMARY
The object of this study was to test the hypothesis that levels of luteinizing hormone (LH), comparable to those circulating at oestrus, inhibit oestrogen secretion from Graafian follicles of sheep. Three experimental approaches were used.
Follicles maintained in organ culture secreted high levels of oestrogen into the medium throughout a 7-day culture period; almost no progesterone was secreted under such conditions. By contrast, oestrogen secretion declined precipitously and progesterone secretion increased rapidly after the addition of LH (0·25 μg–10 μg NIH-LH-S 17/ml) to the culture medium.
In experiments combining in-vivo and in-vitro techniques, follicles were obtained from sheep from which the corpora lutea had been removed 24 h previously. The large follicles explanted from these sheep secreted high levels of oestrogen throughout the 7 days in culture. Insignificant amounts of oestrogen were, however, secreted in culture by large follicles that had been explanted from sheep in which 1 mg LH had been infused between 18 and 24 h after removal of the corpus luteum.
Experiments carried out entirely in vivo showed that intravenous infusion of 1 mg LH into sheep from which the corpora lutea had been removed 18 h previously prevented the ovaries from secreting, during the ensuing 22 h, the large amounts of oestrogen they would otherwise have produced.
The results demonstrate that oestrogen secretion by large Graafian follicles is terminated both in vitro and in vivo by an amount of LH corresponding to that released at oestrus.
THE INFLUENCE OF MATERNAL NUTRITION ON PLASMA HORMONE AND METABOLITE CONCENTRATIONS OF FOETAL LAMBS
Authors: BASSETT J. M. , MADILL DENISE 
Published: December 2008

SUMMARY
Merino ewes whose foetuses had surgically-implanted, indwelling vascular cannulae were used to determine the influence of maternal nutritional status on foetal plasma hormone levels during the last month of gestation. Observations were made during feeding of the ewes on a lucerne chaff diet ad libitum, during restricted feeding on the same diet and during fasting. Foetuses survived for an average of 31 days after the operation and seven out of the ten ewes lambed normally. In both ewes and foetuses, plasma concentrations of insulin were significantly higher 3–12 h after feeding than in prefeeding samples. Similar changes were seen with restricted and ad-libitum feeding. Fasting for 48 h caused significant decreases in insulin levels of both ewes and foetuses, but the decrease in foetal plasma insulin concentration was less than that in ewes. In agreement with earlier studies, foetal and maternal glucose concentrations were closely correlated and foetal fructose concentrations were closely related to foetal glucose concentrations. Foetal plasma insulin concentrations were closely correlated with glucose and fructose concentrations. Plasma growth hormone (GH) levels increased significantly in both ewes and foetuses during fasting. There were also significant increases during fasting in the plasma corticosteroid levels of the ewes, but not in those of their foetuses. Feeding did not cause significant changes in foetal plasma GH or corticosteroid concentrations although maternal GH concentrations were significantly increased and corticosteroid concentrations decreased 3–12 h after feeding on the restricted diet.
The results suggest that alterations in foetal plasma hormone concentrations could play an important role in foetal adaptation to fluctuations in maternal nutrient supply during the last month of gestation.
UPTAKE OF [6,7-3H]OESTRADIOL-17β BY NORMAL AND ABNORMAL HUMAN ENDOMETRIUM
Authors: CROCKER S. G. , MILTON P. J. D. , KING R. J. B. 
Published: December 2008

SUMMARY
Cytoplasmic and nuclear oestradiol-17β binding sites have been measured in human endometrium obtained at different stages of the menstrual cycle and from patients with cystic hyperplasia and endometrial carcinoma. In normal endometrium both sets of sites are maximal at about the time of ovulation. The number of nuclear sites obtained by incubating endometrium with oestradiol-17β in vitro paralleled the number of available cytoplasmic sites.
Cytoplasmic and nuclear binding sites were present in cystic hyperplasia and endometrial carcinomata. There was no correlation between the degree of differentiation of the tumour and its oestradiol-17β binding capacity. All types of endometrium contained variable amounts of 8–10 S and 4–5 S cytoplasmic receptors. The proportions of these receptors were not affected by the presence of the protease inhibitor, p-phenylmethylsulphonyl fluoride.
IMPLANTATION OF OESTROGEN IN THE BRAIN AND THE INDUCTION OF OVULATION IN THE GUINEA-PIG
Authors: BOOTH JANET E. , DONOVAN B. T. 
Published: December 2008

SUMMARY
In the guinea-pig, when bilateral oestrogen implants were placed in the medial basal hypothalamus, anterior hypothalamus or suprachiasmatic area on day 10 of the oestrous cycle, ovarian changes indicative of gonadotrophin secretion were observed on day 15. Similarly located cholesterol implants and oestrogen implants outside this region were without effect. The gonadotrophin release was likely to have been induced by an action of the steroid at the hypothalamic, rather than the pituitary level, since bilateral implants of oestrogen in the pars distalis caused ovarian activation in only one out of eight animals. Signs of normal ovulation were evident in only three out of 19 animals in which oestrogen was implanted in the medial basal hypothalamus on day 10 and left in place for 10 days. The ovaries of some other animals bore the traces of luteal bodies formed in response to the initial exposure to oestrogen; other ovaries contained only large healthy or atretic follicles and spontaneous ovulation was apparently blocked. It is concluded that exposure of the hypothalamo-hypophysial system of the guinea-pig to an increased amount of oestrogen initially stimulates and then inhibits ovulatory gonadotrophin secretion. Tonic gonadotrophin secretion is unaffected.
REPTILIAN OVARIAN STEROIDOGENESIS AND THE INFLUENCE OF MAMMALIAN GONADOTROPHINS (FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE) IN VITRO
Authors: CHAN S. W. C. , CALLARD I. P. 
Published: December 2008

SUMMARY
The synthesis of steroids from [7α-3H]cholesterol, [7α-3H]pregnenolone and [7α-3H]progesterone by lizard and turtle ovarian tissues in vitro was studied. Progesterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone, oestrone and oestradiol were identified as products. In the turtle (Pseudemys), conversion of pregnenolone to progesterone was efficient, but transformation of progesterone to other steroids was relatively slow as indicated by the accumulation of progesterone over the incubation period. In Dipsosaurus, accumulation of radioactivity was greatest in testosterone, the quantities of which continued to increase at each sampling period. The rate of utilization of pregnenolone as a substrate was similar for the two species studied and the quantities of oestrone and oestradiol formed were lower in Pseudemys. The use of progesterone as precursor by Dipsosaurus ovarian tissue revealed a similar pattern of Δ4-steroid metabolism to that obtained with pregnenolone as precursor.
The effects of addition of purified follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on the metabolism of [14C]cholesterol in vitro was studied using Pseudemys follicular tissue. The pattern of cholesterol metabolism was similar to that for pregnenolone in this species. The synthesis of pregnenolone, progesterone, dehydroepiandrosterone and androstenedione in vitro was significantly enhanced in the presence of LH. Follicle-stimulating hormone had no effect on steroid synthesis except for a decrease of androstenedione formation. The stimulatory effect of LH on steroidogenesis in vitro is discussed in relation to the literature suggesting that mammalian FSH, but not LH, stimulates all phases of reptilian ovarian function when injected in vivo.