bluuebunny/crossref_metadata_2025_split huggingface dataset:
UPTAKE AND INTERCONVERSION OF TRITIATED OESTRONE AND OESTRADIOL-17β IN THE INTACT RABBIT IN VIVO
Authors: CROCKER J. M. , THOMAS G. H. 
Published: December 2008

SUMMARY
[6,7-3H]Oestrone was infused into virgin and 24-h post-partum lactating rabbits for a period of 1 h. At the end of the infusion period the concentration of free [6,7-3H]oestrone and [6,7-3H]oestradiol-17β was determined in plasma and in selected tissues (uterus, vagina, muscle, cerebral cortex, hypothalamus and anterior pituitary). Similar studies were carried out on virgin rabbits infused with [6,7-3H]oestradiol-17β. The tissues showed characteristic differences in the concentration of labelled oestradiol-17β and in the ratio labelled oestradiol-17β:oestrone, irrespective of whether the animal was infused with tritiated oestrone or oestradiol-17β. The uterus and vagina contained predominantly oestradiol-17β, while the oestradiol-17β:oestrone ratios of the pituitary and other tissues approximated to that of the plasma.
THE BIOASSAY OF GROWTH HORMONE IN SNELL'S DWARF MICE: EFFECTS OF THYROXINE AND PROLACTIN ON THE DOSE—RESPONSE CURVE
Authors: WALLIS M. , DEW JENNIFER A. 
Published: December 2008

SUMMARY
Pituitary growth hormone has a dose-dependent growth promoting effect in pituitary dwarf mice (Snell's strain), and this effect can be used as the basis of a bioassay for the hormone. Prolactin and thyroxine also promote growth in these animals, and the effects of these hormones in combination with growth hormone were studied, in order to see whether their presence might enhance the precision or sensitivity of the growth hormone assay.
When prolactin and/or thyroxine were administered with growth hormone, the growth response observed was no greater than the sum of the effects of the hormones given separately; in some cases it was less. Neither prolactin nor thyroxine increase the sensitivity or precision of the growth hormone bioassay. The implications of these results for theories about the mechanisms of growth promotion by these hormones are considered.
ASSAY OF CORTISOL, CORTICOSTERONE, 11-DEOXYCORTISOL AND CORTISONE IN OVINE PERIPHERAL AND ADRENAL VENOUS PLASMA
Authors: CLEMENTS A. S. , NEWSOME H. H. 
Published: December 2008

SUMMARY
An assay was devised, using Sephadex LH-20 chromatography and competitive protein binding, to measure cortisol, corticosterone, 11-deoxycortisol and cortisone in a single extract of 4 ml peripheral plasma or 50–300 μl adrenal venous plasma in sheep. The method is especially suited for measuring the low concentrations of these steroids in ovine plasma. Mean values (μg/100 ml) in dexamethasone-suppressed plasma were cortisol, 0·042; corticosterone, 0·004; 11-deoxycortisol, 0·004; and cortisone, 0·021. Mean values (μg/100 ml) in basal plasma were cortisol, 1·11; corticosterone, 0·044; 11-deoxycortisol, 0·020; and cortisone, 0·24. Peripheral concentrations of all four steroids increased in response to corticotrophin, but none increased after angiotensin. Metyrapone administration produced a marked rise in deoxycortisol. The method provided direct evidence that cortisone and deoxycortisol were secreted by the adrenal gland in sheep.
PURIFICATION AND PROPERTIES OF CHORIONIC GONADOTROPHIN FROM TROPHOBLASTIC TISSUE, URINE AND PLASMA OF A PATIENT WITH A HYDATIDIFORM MOLE
Authors: PALA A. , MEIRINHO M. , BENAGIANO G. 
Published: December 2008

SUMMARY
Purified human chorionic gonadotrophin (HCG) fractions were obtained from urine, peripheral plasma and chorionic tissue of a woman with hydatidiform mole by a combination of DEAE-cellulose and DEAE-Sephadex ion exchange chromatography and gel filtration on Sephadex G-100. Homogeneity of the purified fractions obtained was demonstrated by analytical polyacrylamide gel electrophoresis and immunoelectrophoresis. The preparation from plasma had a higher ratio of biological to immunological activity than the urine or tissue preparation. The biological potency of the plasma HCG was 23000 i.u./mg, whereas the urinary and the trophoblastic tissue preparations showed a potency of 20000 and 6500 i.u./mg, respectively.
Further characterization of the three fractions was achieved by analytical isoelectric focusing and determination of the molecular weight. The peak of radioimmunological activity after isoelectric focusing was found to be, in all three cases, at pH 4·90 and the molecular weight obtained after incubation with sodium dodecyl sulphate and urea was around 63000 When the molecular weight was determined after incubation in a medium containing 4 m-urea, sodium dodecyl sulphate and 2-mercaptoethanol two separate fractions were obtained from each of the three preparations. The heavier fraction showed a molecular weight of approximately 35000 and the lighter fraction had a molecular weight of approximately 27000.
SEASONAL VARIATION IN THYROID HORMONOGENESIS IN THE INDIAN GARDEN LIZARD, CALOTES VERSICOLOR
Authors: THAPLIYAL J. P. , CHANDOLA ASHA 
Published: December 2008

SUMMARY
The metabolism of radioactive iodine in the adult male garden lizard, Calotes versicolor, was studied during the course of a year by examination of the following indices of thyroid function: thyroidal 131I uptake, quantitative estimation of labelled iodoamino acids in the thyroid gland and in plasma, and plasma protein-bound iodine. Labelled monoiodotyrosine, di-iodotyrosine and thyroxine were identified and seasonal variations in their proportions demonstrated. Thyroxine was not detected in winter but made its appearance in the spring and summer months. Tri-iodothyronine was not detected at any time of the year in the thyroid of Calotes.
The effects of administration of thyrotrophin (TSH), lowered temperature and dehydration were also studied. TSH augmented 131I incorporation into the thyroid gland significantly but was not effective in stimulating hormonogenesis in winter. While water withdrawal had no effect on thyroidal radioactive iodine uptake, temperature lowered artificially (15 °C) in summer reduced it by half, and altered greatly the proportions of iodoamino acids in the thyroid. The results are discussed in the light of the fragmentary information concerning thyroid function in reptiles.
THE IMMUNOCHEMICAL SPECIFICITY OF ANTISERA TO BOVINE PARATHYROID HORMONE: AN APPROACH TO REGION-SPECIFIC RADIOIMMUNOASSAY
Authors: MURRAY T. M. , KEUTMANN H. T. 
Published: December 2008

SUMMARY
Six different antisera to bovine parathyroid hormone were characterized immunochemically by comparing their reactivity towards amino-terminal (1–29) and carboxyl-terminal (53–84) fragments of the hormone molecule. Three of the antisera were primarily amino-terminally directed. One antiserum contained antibody populations to at least three discrete sites; two other antisera each contained two antibodies directed against each end region of the hormone. By saturating one of these antisera with one or the other of the end fragments of the hormone, specific immunoassays for the amino-terminal and carboxyl-terminal regions of the molecule were developed. Such techniques may be applied to improving the specificity of the radioimmunoassay for parathyroid hormone by eliminating interference from carboxyl-terminal hormonal fragments which circulate in human plasma.
THE STEROIDOGENIC RESPONSE OF ADULT RAT ADRENOCORTICAL CELLS IN MONOLAYER CULTURE
Authors: O'HARE M. J. , NEVILLE A. MUNRO 
Published: December 2008

SUMMARY
Quantitative aspects of corticosteroidogenesis were examined in monolayer cultures of cells from the zona fasciculata and zona reticularis of the adult rat adrenal cortex, maintained for up to 4 months. Corticosterone secretion continued at a steady rate in cultures maintained with corticotrophin (ACTH), the output of maximally stimulated cultures being approximately 12 μg/106 adrenocortical cells/day. In the absence of ACTH, a small amount of 20α-hydroxypregn-4-en-3-one, but no detectable corticosterone, was secreted, resulting in a fluorogenic steroid output 1/125 th of that of maximally stimulated cultures. Restimulation with ACTH of cultures maintained for up to 2 months in its absence resulted in maximum levels of corticosterone secretion after 4–5 days of continuous ACTH treatment. The levels of corticosterone secretion attained on restimulation were similar to those observed in cultures maintained with ACTH from the out set. Withdrawal of ACTH resulted in a fall in steroid output which took 10 days to reach final unstimulated levels. Trophic stimulation of corticosteroidogenesis with a similar time-course was obtained with both cyclic AMP and dibutyryl cyclic AMP, the latter being the more effective.
LUTEINIZING HORMONE AND PROGESTERONE IN PERIPHERAL BLOOD DURING THE OVULATORY CYCLE OF THE HEN GALLUS DOMESTICUS
Authors: FURR B. J. A. , BONNEY ROSEMARY C. , ENGLAND ROWENA J. , CUNNINGHAM F. J. 
Published: December 2008

SUMMARY
Radioimmunoassays were used to estimate luteinizing hormone (LH) and progesterone in samples of blood taken from individual hens at frequent intervals throughout their respective ovulatory cycles. A consistent pattern in the plasma levels of both hormones was observed. Significantly more LH and progesterone was present in plasma 4–7 h before ovulation than at other times during the cycle. An increase in the level of progesterone either preceded that of LH or the two hormones increased simultaneously. At no time did an increase in the level of LH occur before the rise in progesterone. In those birds which did not ovulate during the experimental period the levels of both hormones remained low. The significance of these findings in relation to the neuroendocrine control of ovulation in the hen is discussed.
THE EFFECT OF PROGESTERONE AND OESTRADIOL ON IMMATURE MOUSE UTERI MAINTAINED AS ORGAN CULTURES
Authors: GRANT P. S. 
Published: December 2008

SUMMARY
Uterine horns from immature mice were cultured for 2 days in Trowell's T8 medium containing 20% foetal calf serum and either ethanol (0·125%), oestradiol-17β (5 μg/ml), progesterone (5 μg/ml) or progesterone plus oestradiol (5 μg + 5 μg/ml). The uteri were fixed in Bouin's fluid and the degree of closure of the lumen was assessed by an independent observer after examination of histological sections.
Uteri treated with oestradiol alone usually did not differ from those treated with ethanol: progesterone treatment either alone or in combination with oestradiol led to luminal closure.
THE EFFECT OF CERTAIN STILBOESTROL ANALOGUES ON PLASMA PROLACTIN AND TESTOSTERONE IN THE RAT
Authors: DANUTRA VARAPAN , HARPER M. E. , BOYNS A. R. , COLE E. N. , BROWNSEY B. G. , GRIFFITHS K. 
Published: December 2008

SUMMARY
Oestradiol-17β, diethylstilboestrol (DES), dl-dihydrodibutylstilboestrol (dl-DHBS) and meso-dihydrodibutylstilboestrol (meso-DHBS) were injected intramuscularly into male Sprague-Dawley rats in a daily dose of 100 μg for a period of 10 days. Oestradiol-17β and DES decreased the weight of the prostate and seminal vesicles to the same extent, whereas meso-DHBS was less effective. dl-DHBS was almost inactive. Only oestradiol-17β and DES caused a decrease in the weight of the testes. The adrenal glands increased in weight after administration of either oestradiol-17β, DES or meso-DHBS.
Four hormones in the plasma were measured: testosterone, androstenedi-one, prolactin and interstitial cell-stimulating hormone (ICSH). DES decreased the plasma concentration of both ICSH and testosterone. Oestradiol-17β and meso-DHBS administration resulted in a lowering of the plasma testosterone concentration with no effect on ICSH. Oestradiol-17β, DES and meso-DHBS markedly increased plasma prolactin concentrations. dl-DHBS appeared to have little biological effect causing only very small changes in all the parameters investigated.
CONCENTRATION OF PROGESTERONE IN SYSTEMIC PLASMA OF GOATS: EFFECTS OF VARIOUS ROUTES OF ADMINISTRATION
Authors: DHINDSA D. S. , RESKO J. A. , METCALFE J. 
Published: December 2008

SUMMARY
The effect of various routes of administration on the plasma concentrations of progesterone was studied in Pygmy goats. Oral administration, even in extremely high doses, gave low plasma concentrations which returned to normal within 24 h. Progesterone given by subcutaneous or intra-abdominal implantation in silicone rubber (Silastic) envelopes caused a marked rise in the plasma concentration of progesterone, values reaching 10–30 ng/ml at 10–20 days but then declining. A fall in plasma concentration despite continued administration was also observed with daily intramuscular injections of large doses of progesterone. This observation suggests that some physiological mechanism prevents sustained high plasma levels of this hormone.
THE LACTOGENIC EFFECTS OF PROLACTIN AND GROWTH HORMONE ON MAMMARY GLAND EXPLANTS FROM VIRGIN AND PREGNANT SPRAGUE-DAWLEY RATS
Authors: HALLOWES R. C. , WANG D. Y. , LEWIS D. J. 
Published: December 2008

SUMMARY
Explants of mammary glands from mature virgin and pregnant Sprague—Dawley rats were maintained in organ culture for up to 96 h. The effects of insulin, corticosterone, ovine prolactin and bovine growth hormone on the synthesis of DNA, RNA and casein in the explants were studied.
DNA synthesis in explants from virgin rats was maintained by insulin but was not increased by the addition of the other hormones tested. DNA synthesis in explants from pregnant rats was increased by insulin, and the addition of corticosterone and either prolactin or growth hormone to the culture medium increased this synthesis. The rate of RNA synthesis in explants from virgin rats was similar in medium 199 with or without additional hormones. RNA synthesis in explants from pregnant rats was increased by the addition of insulin or insulin plus corticosterone to the medium. In explants from both virgin and pregnant rats the maximal rate of hormone-stimulated DNA or RNA synthesis occurred during the first 24 h of culture.
Casein synthesis, as measured by the uptake of 32P-labelled orthophosphate by explants from virgin and pregnant rats, was increased by insulin plus corticosterone plus either prolactin or growth hormone. The rate of casein synthesis was maximal between 48 and 72 h and was reduced by actinomycin D. In the pregnant rats no significant differences were demonstrated between the effects of the hormones on DNA, RNA or casein synthesis in explants from the 5th, 10th, 16th or 19th day of pregnancy.
BINDING OF 5α-ANDROSTANE-3α,17β-DIOL TO HUMAN PLASMA PROTEINS
Authors: CLARK A. F. , BIRD C. E. 
Published: December 2008

SUMMARY
The binding of 5α-androstane-3α,17β-diol to human plasma proteins was studied by equilibrium dialysis. The mean value of 96·6% for men was significantly less than that of 97·5% for women. These values are higher than those found for 5α-dihydrotestosterone (95·0 and 97·3%, respectively) and for testosterone (92·4 and 95·3%, respectively). When the distribution of labelled steroid in the different protein fractions was studied by paper electrophoresis, male plasma showed a larger fraction of 5α-androstane-3α,17β-diol radioactivity in the albumin fraction and less in the β-globulin area than did female plasma. Similar finding were made when 5α-dihydrotestosterone was studied. No inter-α-globulin peak of radioactivity was found for 5α-androstane-3α,17β-diol and 5α-dihydrotestosterone as occurs for testosterone. Albumin binds more 5α-androstane-3α,17β-diol than 5α-dihydrotestosterone or testosterone when studied by equilibrium dialysis and this is due to a higher apparent association constant between albumin and the dihydroxysteroid.
PROGESTERONE SECRETION BY THE SHEEP CORPUS LUTEUM AFTER REPEATED INFUSIONS OF LUTEINIZING HORMONE AND HUMAN CHORIONIC GONADOTROPHIN
Authors: BAIRD D. T. , COLLETT R. A. 
Published: December 2008

SUMMARY
The response of the ovine corpus luteum to repeated infusions of luteinizing hormone (LH) or of human chorionic gonadotrophin (HCG) was tested in four ewes with the left ovary autotransplanted to the neck. Constant infusion for 1 h of either LH (100 or 1000 μg/h) or HCG (200 i.u./h) via the ovarian artery stimulated a temporary increase in secretion of progesterone which fell to control levels by 60 min. Ovarian blood flow increased progressively (P < 0·05) throughout the infusion of gonadotrophin in three of the five experiments. A second infusion of either gonadotrophin after a further control hour failed to stimulate progesterone secretion. These results suggest that ovine luteal tissue rapidly becomes refractory to the steroidogenic effect of LH in vivo.
OBSERVATIONS ON THE RELEASE AND CLEARANCE OF NEUROPHYSIN AND THE NEUROHYPOPHYSIAL HORMONES IN THE RAT
Authors: FORSLING MARY L. , MARTIN MARION J. , STURDY J. C. , BURTON ANGELA M. 
Published: December 2008

SUMMARY
Circulating levels of neurophysin, oxytocin and vasopressin were determined in rats under various physiological conditions using bovine neurophysin as the reference standard. Under resting conditions the mean plasma concentration of immunoreactive neurophysin was 6·2 ± 2·4 ng/ml while oxytocin and vasopressin were undetectable.
Neurophysin and vasopressin were released in response to haemorrhage in Wistar and heterozygous Brattleboro rats; in the homozygous strain haemorrhage resulted in a release of oxytocin and neurophysin. Infusion of 0·1 M-calcium chloride into Wistar rats caused a rise in plasma neurophysin, oxytocin and vasopressin. The half-times for the disappearance from the plasma of arginine-vasopressin and neurophysin in the circulation were 1·6 ± 0·8 (S.D.) and 3·4 ± 0·9 min respectively.
THE MILK-EJECTION REFLEX OF THE RAT: AN INTERMITTENT FUNCTION NOT ABOLISHED BY SURGICAL LEVELS OF ANAESTHESIA
Authors: LINCOLN D. W. , HILL ALISON , WAKERLEY J. B. 
Published: December 2008

SUMMARY
Milk ejection (ME) was studied in the lactating rat by the measurement of intramammary pressure, milk yield and behaviour. An intermittent pattern of ME was observed, both in conscious rats and in rats anaesthetized with tribromoethanol, pentobarbitone sodium and ethyl carbamate. Milk ejection was never seen as a reflex response with the onset of the suckling stimulus; the latency to the first ME varied from 10 min in the conscious rat to > 60 min during deep anaesthesia. Thereafter, ME occurred at regular intervals ranging from 3 to 5 min under optimal conditions to > 15 min during less favourable circumstances, though the young were content to suckle continuously for several hours irrespective of whether they obtained milk.
Each ME was associated with an abrupt and uniform rise in intramammary pressure and simulation of the individual ME was obtained by a rapid i.v. injection of 1 mu. oxytocin. The pups reacted immediately to the rise in pressure with a synchronized extensor reaction and a vigorous increase in suckling which lasted for about 10 s. There was, however, no apparent change in the suckling stimulus to account for the release of endogenous oxytocin some 10–20 s prior to these events. Milk ejection was a reflex phenomenon, nonetheless, for the removal of the pups abolished the intermittent release of oxytocin.
The rise in intramammary pressure was associated directly with the ejection of the milk and the pups abruptly increased in weight. Yields of 10–12 g were obtained from both conscious and anaesthetized rats after 18 h of separation from their young. Most of this milk was expressed in the first ten milk ejections.
Mammary distension and the size of the litter were important parameters determining the pattern of ME. The incidence of ME was appreciably lower in unseparated rats whether anaesthetized or not and in separated rats after prolonged suckling or artificial removal of the milk. A similar reduction was encountered when the number of suckling pups was changed from ten to five.
The physiological principles of the ME reflex in the rat are discussed and a theoretical model is presented.
THE EFFECT OF LOW DOSES OF HUMAN CHORIONIC GONADOTROPHIN ON THE FERTILIZING ABILITY OF HAMSTER EPIDIDYMAL SPERMATOZOA
Authors: LUBICZ-NAWROCKI C. M. 
Published: December 2008

SUMMARY
The fertilizing ability of spermatozoa in ligated caudae epididymides of golden hamsters was reduced to approximately 25% of the control level after 12 daily s.c. injections of 10 i.u. human chorionic gonadotrophin (HCG), but spermatozoa retained normal fertilizing ability after treatment with higher doses of HCG (30 and 40 i.u./day). This antifertility effect of HCG was mediated through the testes since removal of one testis reduced the adverse effect of 10 i.u. HCG/day by approximately 75% while spermatozoa retained normal fertilizing ability in animals bilaterally castrated and treated with testosterone. Additional experiments revealed that 12 daily injections of 250 μg testosterone significantly reduce fertilizing ability although treatment with 500 μg testosterone daily for the same period had no effect. It was found, also, that the antifertility effect produced by treatment with 10 i.u. HCG daily for 12 days was similar to that after 12 daily injections of 3·5 μg oestradiol benzoate (OB). While 250 μg testosterone/day in combination with OB (3·5 μg/day) augmented the antifertility effect of this hormone, 500 μg testosterone daily prevented to a small but significant extent, the antifertility effects of HCG and OB at these doses. By contrast to their effects on fertilizing ability, testosterone, HCG and OB had no significant effect on seminal vesicular fructose concentration which remained high in each experimental group. It is suggested that the antifertility effect of low doses of HCG results from stimulation of testicular secretion of testosterone and subsequent conversion of limited but significant amounts of testosterone into oestrogens, either in the testis or peripherally, which then antagonize the effects of testosterone in the cauda epididymidis.
EARLY EFFECTS OF STILBOESTROL ON GROWTH HORMONE AND PROLACTIN SECRETION AND ON PITUITARY MITOTIC ACTIVITY IN THE MALE RAT
Authors: LLOYD H. M. , MEARES J. D. , JACOBI JOAN 
Published: December 2008

SUMMARY
The effects of a single injection of 1 mg diethylstilboestrol dipropionate on pituitary mitotic activity and on secretion of growth hormone and prolactin were investigated in male rats on each of the first 15 days following the single dose and then at intervals for a total period of 63 days. Mitotic activity increased to a maximum on day 4 and then gradually diminished. Serum growth hormone was moderately increased during the 2nd week and serum prolactin showed a gradual rise with a return to normal on day 63. In the pituitary gland, growth hormone concentration diminished until day 28, whereas prolactin rose quickly at first, maintained a raised level and increased further on day 43. During the first 12 days, pituitary weight was significantly correlated with serum growth hormone and prolactin concentration. During days 13–28, serum prolactin, but not growth hormone, was significantly correlated with the pituitary mitotic index.