bluuebunny/crossref_metadata_2025_split huggingface dataset:
REVERSIBLE BINDING OF LABELLED AND NON-LABELLED THYROTROPHIN BY INTACT THYROID TISSUE IN VITRO
Authors: MANLEY S. W. , BOURKE J. R. , HAWKER R. W. 
Published: December 2008

SUMMARY
125I-Labelled thyrotrophin (TSH) showed saturable binding to hyperplastic guinea-pig thyroid slices in vitro, but not to kidney, adrenal, liver, testis or salivary gland slices. Two populations of binding sites were demonstrated: high order sites showed an affinity constant of 3·8 × 1081/mol and a capacity of 8 × 103 molecules of TSH/cell; low order sites, affinity constant of 2·9 × 1071/mol and capacity of 8 × 104 molecules/cell. The highorder sites saturate at about 1 mu./ml, approximately the level producing maximal in-vivo and in-vitro responses. Binding of 125I-labelled TSH was reversible, the released hormone appearing substantially unchanged as assessed by chromatographic behaviour and antiserum binding. Release of unlabelled TSH from pre-incubated thyroid slices was demonstrated by bioassay. Bovine thyroid slices were found to have a lower capacity for binding than hyperplastic guinea-pig slices.
SERUM LIPID PATTERN IN CHICKENS OF THE OBESE STRAIN
Authors: RUDAS BARBARA , WICK G. , COLE R. K. 
Published: December 2008

SUMMARY
Blood sugar, the serum concentration of total lipids, total glycerol, cholesterol and phosphatides were determined in chickens from the Obese strain (OS) of White Leghorns. Over 90% of these chickens are afflicted with a spontaneously occurring autoimmune thyroiditis and show clinical symptoms of hypothyroidism. Blood glucose levels were increased above normal limits in OS chickens up to 5 weeks of age. Significantly increased serum lipid concentrations were found in the OS chickens at the ages of 1, 5, 8 and 15 weeks, while 3-week-old OS chickens showed almost normal serum lipid levels. A single intravenous injection of heparin in a dose which prolonged bleeding time, had no 'clearing effect' on the serum of OS birds. Insulin given subcutaneously for 4 days had no effect on blood sugar but decreased the serum phosphatides and total lipid concentrations. The short-term administration of high doses of thyroxine significantly lowered the serum levels of total lipids, cholesterol, phosphatides and total glycerol.
THE EFFECT OF UNILATERAL OVARIECTOMY IN THE NEONATAL MOUSE ON FOLLICULAR DEVELOPMENT
Authors: PETERS HANNAH , BRAATHEN BRITT 
Published: December 2008

SUMMARY
The remaining ovary of a 14-day-old mouse after unilateral ovariectomy (ULO) on day 2 showed the same number and stages of follicles as an ovary in an intact animal of the same age. No increase in the number of developing follicles nor development to more advanced stages occurred. Hemispaying in the neonatal period did not alter the number of follicles that started growth nor their speed of development in the subsequent 12 days. However, premature follicle fluid accumulation and a widening of the theca layer in early growing follicles were characteristically found in the remaining ovary. The failure of the remaining ovary to increase its complement of large follicles is probably due to the fact that those follicle stages (i.e. large follicles) which are able to react to stimulation by follicle-stimulating hormone in the prepubertal and adult ovary are as yet lacking in the early infant ovary. However, reaction to luteinizing hormone can already be expressed and is shown by premature follicle fluid accumulation and widening of the theca layer. The changes seen are interpreted as a reaction of the remaining ovary to a relative increase in an unchanged amount of available gonadotrophin rather than to a change in the pituitary—gonadal feedback mechanism.
MEASUREMENT OF CANINE PITUITARY PROLACTIN
Authors: SALUJA P. G. , GRONOW M. , HAMILTON J. M. 
Published: December 2008

SUMMARY
Isoelectric focusing in polyacrylamide gel followed by staining with Coomassie brilliant blue was used for the densitometric estimation of ovine prolactin standard and canine pituitary prolactin. The results were compared with those obtained by conventional polyacrylamide gel electrophoretic procedures and isoelectric focusing was found to be a valid technique for the estimation of prolactin and to offer greater technical convenience.
The mobility of ovine and canine prolactin was similar in isoelectric focusing and gel electrophoresis. The isoelectric point of ovine and canine prolactin was found to be 6·17 and 6·61 respectively.
Constant levels of prolactin were found in the pituitaries of bitches at oestrus.
INVOLVEMENT OF THE UTERINE BLOOD VESSELS IN THE REFRACTORY STATE OF THE UTERINE STROMA WHICH FOLLOWS OESTROGEN STIMULATION IN PROGESTERONE-TREATED MICE
Authors: MARTIN L. , HALLOWES R. C. , FINN C. A. , WEST D. G. 
Published: December 2008

SUMMARY
Increases in uterine capillary permeability after the injection of oestradiol into spayed mice, appeared to be caused by the development of vascular fenestrations and not by the separation of adjoined endothelial cells. Progesterone did not prevent the uterine weight, oedema and vascular responses to the first of two injections of oestradiol but inhibited those to the second. It was concluded that the failure of repeated oestrogen-treatment to produce uterine oedema in progesterone-treated mice resulted from the refractory state which develops after the first injection and which extends to the endometrial vasculature.
THE DISTRIBUTION AND METABOLISM OF LABELLED CORTICOSTEROIDS IN THE DUCK (ANAS PLATYRHYNCHOS)
Authors: HELTON E. D. , HOLMES W. N. 
Published: December 2008

SUMMARY
After the injection of [1,2-3H]corticosterone into ducks, no unaltered free [1,2-3H]corticosterone was found in either bile, gut contents or cloacal fluid. All the [1,2-3H]corticosterone metabolites in cloacal fluid had similar chromatographic mobilities. A portion of these metabolites was steroid ester sulphate but enzymic hydrolysis suggested that only a small fraction of the sulphate was conjugated to [1,2-3H]corticosterone. The amount of ester sulphate in samples of cloacal fluid, however, was highly variable.
After the injection of [1,2-3H]aldosterone one-fifth of the total radioactivity in urine was free [1,2-3H]aldosterone but none was found in the bile and gut contents. Chromatographic purification of the [1,2-3H]aldosterone metabolites in cloacal fluid showed two significant peaks and both peaks contained steroid ester sulphates. Enzymic hydrolysis of the tritiated material showed that each peak also contained a glucuronide of [1,2-3H]aldosterone.
The effect of the entero-hepatic circulation on the excretion of tritiated metabolites by the kidney was also examined. Diversion of bile from the duodenum prevented the entry of radioactive material into the gut. The reduced reabsorption of tritiated corticosterone and tritiated aldosterone metabolites from the gut, however, did not affect the amount of tritium excreted by the kidneys. In the case of both hormones, some of the reabsorbed metabolite which had been extracted by the liver was released and re-entered the peripheral blood via the hepatic circulation. The stress of surgery in both the control birds and the birds with bile catheters caused the distribution of [1,2-3H]corticosterone and the tritiated corticosterone metabolites to change; a significantly smaller percentage of the injected radioactivity was recovered from the tissues and excretory fluids. This response to stress was not observed in the [1,2-3H]aldosterone injected birds.
When partially purified metabolites of [1,2-2-3H]corticosterone and [1,2-3H]aldosterone were injected into the lumen of the gut, the rate of uptake of the tritiated corticosterone metabolites was higher than that of the tritiated aldosterone metabolites. But, when the metabolites of [1,2-3H]corticosterone and [1,2-3H]aldosterone were injected intravenously, and the rate of the intestinal reabsorption of the metabolites was not limiting, the rates of tritium excretion by the kidneys were the same. The volumes of distribution and metabolic clearance rates of the partially purified [1,2-3H]corticosterone and [1,2-3H]aldosterone metabolites were significantly different from one another and the metabolites could be readily distinguished physiologically as well as chromatographically. The pattern of distribution and the disappearance from plasma of i.v. administered synthetic [1,2-3H]corticosterone-21-SO4 was also distinguishable from the naturally occurring metabolites of [1,2-3H]corticosterone.
HORMONAL REQUIREMENTS FOR THE MAINTENANCE OF LUTEAL FUNCTION IN HYPOPHYSECTOMIZED, PSEUDOPREGNANT RATS
Authors: TAKAYAMA MASAOMI , GREENWALD G. S. 
Published: December 2008

SUMMARY
Pseudopregnant rats with traumatized uteri were hypophysectomized on day 6 and injected with various hormones over the next 4 days. Luteal function was assessed on day 10 of pseudopregnancy by weighing deciduomata and determining luteal and plasma levels of progesterone by a competitive protein-binding assay. Daily treatment with 0·25 mg prolactin restored plasma and luteal levels to the values of intact pseudopregnant animals; however, the deciduomata weighed only 55% of control values. Combining oestrone with prolactin restored deciduomata weight to control values without affecting peripheral progesterone levels.
Either 200 μg of follicle-stimulating hormone (FSH) or 5 μg luteinizing hormone (LH) could be substituted for oestrone, in conjunction with prolactin, to increase deciduomata weight to control values. Moreover, the combination of prolactin with FSH or LH significantly increased peripheral plasma levels of progesterone beyond the effects of prolactin alone. Higher doses of LH were luteolytic as shown by decreased deciduomata weight and considerable variation in plasma and luteal values of progesterone. LH given alone — either in saline or polyvinyl pyrrolidine — failed to maintain any of the parameters of luteal activity mentioned above.
The results reaffirm the primacy of prolactin in vivo as the principal luteotrophic hormone of the rat and indicate that selected doses of LH or FSH play an additive role in further increasing peripheral levels of progesterone.
DISTRIBUTION OF OESTROGEN RECEPTORS IN CELL FRACTIONS OF HUMAN UTERINE TISSUE
Authors: EVANS L. H. , HÄHNEL R. 
Published: December 2008

SUMMARY
[3H]Oestradiol-17β binding by cytoplasmic and nuclear fractions of human uterine tissue homogenates was studied by intact tissue and cell-free incubation techniques. In the absence of divalent cations, swelling and rupture of endometrial nuclei led to a loss of nuclear receptor complex into the cytoplasmic fraction of the homogenate. Divalent cations at a concentration of 0·003 mol/l, however, caused precipitation of the cytoplasmic receptor complex, inhibited [3H]oestradiol-17β binding by the cytoplasmic receptor and inhibited the extraction of soluble nuclear receptor complex. These effects were minimal when 0·001 m-magnesium ions were added to the sucrose—tris buffer. Studies of the distribution of oestrogen receptors in homogenates of human uterine tissue in 0·001 m-magnesium—sucrose—tris buffer revealed the presence of a soluble and an insoluble nuclear receptor complex. More of the nuclear receptor complex was obtained in the soluble form when the incubation temperature was raised from 25 to 37 °C. Evidence is presented for the transfer of [3H]oestradiol-17β from the cytoplasmic to the nuclear fractions by a temperature-dependent process and for the binding of [3H]oestradiol-17β by nuclear receptors in the absence of the cytoplasmic fraction.
THE RATE CONSTANTS FOR THE INTERACTION OF CORTISOL AND TRANSCORTIN, AND THE RATE OF DISSOCIATION OF TRANSCORTIN-BOUND CORTISOL IN THE LIVER
Authors: PATERSON J. Y. F. 
Published: December 2008

SUMMARY
The apparent rate of dissociation of transcortin-bound cortisol in human plasma was measured. After establishing equilibrium between plasma proteins and endogenous and added [3H]cortisol, this was perturbed by addition of a known amount of exogenous cortisol. Plasma protein-bound [3H]cortisol was then measured by gel filtration at timed intervals.
This system can be described by six differential equations, one each for unbound, albumin-bound and transcortin-bound cortisol and [3H]cortisol. The rate constants for the transcortin—cortisol reaction were estimated by numerical solution of these equations, using arbitrary rate constants for the albumin—steroid reaction.
At 2 °C the dissociation of transcortin-bound cortisol has a rate constant of 0·00041 s−1, at 10 °C 0·00179 s−1 and at 22 °C 0·0353 s−1. At 37 °C the reaction was very rapid and equilibrium appeared to be attained in less than 5 s. The rate constant could only be estimated by using the Arrhenius equation, In (k) = const + E/RT, and was found to be 0·633 s−1.
The rate constants for cortisol—plasma protein interaction were applied to a differential equation model for the splanchnic uptake of cortisol. Using experimental measurements of the visceral and hepatic uptake of cortisol in sheep the rate constant for the visceral removal of cortisol was found to be 0·0299 ± 0·0065 (s.e.m.) s−1 and the hepatic constant was 0·4674 ± 0·0540 (s.e.m.) s−1. In normal conscious sheep the total splanchnic uptake of cortisol appeared to be derived 42% from unbound, 31% from albumin-bound and 27% from transcortin-bound steroid.
ANDROGENIZATION OF THE NEONATAL FEMALE RAT WITH VERY LOW DOSES OF ANDROGEN
Authors: SHERIDAN P. J. , ZARROW M. X. , DENENBERG V. H. 
Published: December 2008

SUMMARY
The administration of a high dose of androgen on a single day to a neonatal female rat has been shown repeatedly to induce persistent vaginal cornification (PVC). However, this type of treatment does not parallel the continuous androgen secretion present in the male, and the high doses that have been used could represent a pharmacological and not a physiological effect. Experiments were carried out to determine the minimal effective dose of testosterone propionate (TP) needed to cause PVC when the androgen is administered to the neonatal rat for the first 10 days of life or as a long-acting ester. Injection of 1, 3 or 9 μg TP on days 1–10 of life in female rats induced PVC in adulthood. All three doses were found to be more effective than a testicular transplant on day 1. In female rats injected with low doses of TP twice daily for the first 10 days of life, PVC was shown between 90 and 100 days of life in 21 out of 22 animals given 0·5 μg TP/injection, and in eight out of 22 animals given 0·05 μg TP/injection. In an experiment where female rats were given a single injection of 0·1, 1·0 or 10·0 μg TP, or 0·1 or 1·0 μg testosterone cyclopentylpropionate (TC, a long-acting androgen) on the first day after birth, PVC occurred at 90–100 days of age in 15 of the 18 animals which were injected with 10 μg TP, in none of the 17 animals which were injected with 1 μg TP, and in 10 of 11 animals which were injected with 1 μg TC. The effects of all treatments on vaginal opening, first oestrus, ovarian weight, body weight and sexual behaviour are reported. The use and implications of low dose regimens are discussed in relation to the construction of an experimental model for the study of sexual differentiation.
INITIATION OF PARTURITION IN THE RABBIT BY MATERNAL AND FOETAL ADMINISTRATION OF CORTISOL: EFFECT OF RATE AND DURATION OF ADMINISTRATION: SUPPRESSION OF DELIVERY BY PROGESTERONE
Authors: NATHANIELSZ P. W. , ABEL MARGARET 
Published: December 2008

SUMMARY
Continuous infusion of cortisol at rates from 0·31 to 1·24 mg/h into pregnant rabbits from day 21 of pregnancy onwards induced delivery in approximately 72 h. Similar rates of infusion into the foetal amniotic sac induced delivery with a shorter latency. Maternal infusion of 1·24 mg cortisol/h produced parturition providing it was continued for at least 24 h. If after this period the infusion was terminated, delivery still occurred after a further 48 h (i.e. 72 h in all). Progesterone administration to the mother blocked the effect of cortisol administered by the maternal or foetal route.
THE KINETICS OF OESTRADIOL-17β METABOLISM IN THE SHEEP
Authors: CHALLIS J. R. G. , HARRISON F. A. , HEAP R. B. 
Published: December 2008

SUMMARY
The metabolic clearance rate of oestradiol-17β from whole blood and its conversion to oestrone and oestradiol-17α were measured in pregnant and non-pregnant (cyclic, lactating and anoestrous) sheep using tracer kinetic techniques. The metabolic clearance rate was much the same in sheep in different reproductive states (mean in all animals (±s.e.m.) = 2·449 ± 0·155 1/min). The highest values were reached on days 143–145 of pregnancy (3·287 ± 0·3351/min). The mean conversion ratio of oestradiol-17β to oestrone was 17·0 ± 2·2%, and that of oestradiol-17β to oestradiol-17α was 14·1 ± 1·1%. The production rate of oestradiol-17β increased from 0·007 to 0·103 μg/min up to 3 days before parturition to 0·035–1·257 μg/min during the last 12 h of pregnancy.
During the continuous infusion of [3H]oestradiol-17β and when a steady state had been reached, approximately 20–30% of the radioactivity in whole blood could be extracted with ether. Of this radioactivity more than 90% was attributable to labelled oestradiol-17β, oestrone and oestradiol-17α in jugular blood, though only about 70% could be accounted for as these oestrogens in uterine venous blood.
IDENTIFICATION AND MEASUREMENT OF SULPHATE-CONJUGATED NEUTRAL STEROIDS IN THE INTESTINAL CONTENTS OF EARLY AND MID-TERM FOETUSES
Authors: HUHTANIEMI I. , VIHKO R. 
Published: December 2008

SUMMARY
Sulphate-conjugated neutral steroids in the intestinal contents of early and mid-term human foetuses (14–20 weeks of gestation) were investigated by gas—liquid chromatography and gas chromatography—mass spectrometry. Twenty-four neutral steroids were found in the monosulphate fraction and 21 in the disulphate fraction. The total concentration of these steroids varied between 9·6 and 15·3 mg/100 g meconium wet weight, about half being monosulphates and half disulphates. Steroids with a 3β-hydroxy-5-ene structure were found and also saturated steroids which carried hydroxyl groups at carbons 3, 11, 15, 16, 17, 18, 19, 20 or 21. Among them were steroids not previously detected in human foetal compartments. Thus, the foetal meconium is both qualitatively and quantitatively the richest foetal source of neutral steroid sulphates so far investigated.
The present results together with those reported in the literature show that in the course of pregnancy there is a many-fold increase in the steroid concentration of the foetal intestinal contents. This is most obvious in the case of saturated C19 steroids and polar pregnane derivatives. Reduction of the 20-ones to 20β-ols seems to be more extensive towards the end of pregnancy. 5, 16-Pregnadienes and 3β-hydroxy-5β-pregnanes are present in higher concentrations in early pregnancy.
EFFECT OF OVARIAN HORMONES AND SYNTHETIC PROGESTINS ON VAGINAL SIALIC ACID IN THE RAT
Authors: GALLETTI F. , GARDI R. 
Published: December 2008

SUMMARY
Total amount and concentration of vaginal sialic acid were determined in rats after ovariectomy and treatment with oestradiol, progesterone, norethindrone acetate and quingestanol acetate. Sialic acid concentration increased after ovariectomy and decreased after subsequent treatment with oestradiol. Progesterone had no effect on sialic acid concentration in spayed rats. The synthetic progestins norethindrone acetate and quingestanol acetate, given orally, showed a diphasic effect, increasing vaginal sialic acid concentration at low doses and decreasing it at higher doses. These results are discussed in the light of the oestrogenic properties of progestins derived from 19-nortestosterone.
PROLACTIN PRODUCTION AND LACTOGENESIS IN RATS AFTER OVARIECTOMY IN LATE PREGNANCY
Authors: SIMPSON A. A. , SIMPSON M. H. W. , KULKARNI P. N. 
Published: December 2008

SUMMARY
Ovariectomy on day 17 of pregnancy in rats that normally give birth on day 23 induced lactogenesis and foetal resorption but did not alter the pattern of change in pituitary or plasma prolactin concentration. Plasma prolactin levels increased significantly in both ovariectomized and sham-operated animals from days 18–22 of pregnancy. This suggests that factors other than ovarian products control the rise in late pregnancy of plasma prolactin in the rat. The results support earlier reports that progesterone withdrawal may be the lactogenic trigger in the rat.
EFFECT OF PERPHENAZINE DURING LATE PREGNANCY ON PROLACTIN PRODUCTION AND LACTOGENESIS IN THE RAT
Authors: SIMPSON A. A. , SIMPSON M. H. W. , KULKARNI P. N. 
Published: December 2008

SUMMARY
Perphenazine given on day 18 of pregnancy and each day following caused large increases in plasma prolactin levels in rats as measured on days 19–23. Pituitary prolactin was depleted on day 19, but subsequently returned to slightly above control values. Adrenal weight was significantly increased by perphenazine treatment suggesting increased production of adrenocorticotrophin and glucocorticoids. The increased prolactin levels caused no significant change on any day in either mammary lactose, glucose, RNA or DNA concentrations or the RNA:DNA ratio. The findings support earlier reports that an increased level of plasma prolactin during pregnancy does not by itself induce lactogenesis in the rat.
OESTRONE METABOLISM IN PREGNANT AND LACTATING GOATS
Authors: CHALLIS J. R. G. , LINZELL J. L. 
Published: December 2008

SUMMARY
Since blood oestrogen levels are much higher during pregnancy in the goat than in the sheep a continuous isotope infusion technique was used to study oestrone metabolism in five experiments on two goats during late pregnancy and early lactation. The metabolic clearance rate was similar to that in the sheep in all experiments (mean value ± s.e.m., 4·02 ± 0·25 1/min); therefore the high blood oestrone concentrations in late pregnancy (851–2043 pg/ml) were due to high oestrone production rates (4·22–7·54 μg/min). There was some conversion of oestrone to oestradiol-17β by the mammary glands and other tissues (mean conversion ratio 17·1%) and a little (< 10%) binding of oestrone to erythrocytes. The uptake of oestrone by the mammary gland corresponded to < 3% of the total production rate. These results are compared with those obtained for other steroid hormones (progesterone, cortisol) in the goat and sheep.
THE EFFECT OF HYPOTHALAMIC DEAFFERENTATION UPON THE ULTRASTRUCTURE AND HORMONE CONTENT OF THE PARAVENTRICULAR NUCLEUS
Authors: DYER R. G. , DYBALL R. E. J. , MORRIS J. F. 
Published: December 2008

SUMMARY
The ultrastructure and hormone content of the paraventricular nucleus was studied in female rats after surgical isolation of the hypothalamus (by preparation of hypothalamic islands) from the rest of the brain for 48 h. When compared with control animals no quantitative changes were observed in the proportion of cytoplasm occupied by endoplasmic reticulum, Golgi apparatus and mitochondria or in the number of lysosomes/100 μm2 of cytoplasm. However, there was a very significant (P < 0·001) increase in the number of neurosecretory granules observed in the perikarya of paraventricular cells in the deafferentated preparations.
Bioassay of hypothalamic extracts for milk ejection and antidiuretic activities showed that there was a significant increase (P < 0·05) of the former in hypothalamic islands. The increase was greatest in the paraventricular region (P < 0·01). The hypothalamic content of antidiuretic activity was not changed significantly by deafferentation.
The results demonstrate that the amount of milk-ejection activity in the paraventricular nucleus is related to the number of neurosecretory granules and raises the intriguing question of why deafferentation of the hypothalamus influences its milk-ejection activity more than its antidiuretic activity.