bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHANGES IN SIALIC ACID IN THE TESTIS AND EPIDIDYMIS OF THE RAT DURING THE ONSET OF PUBERTY
Authors: RAJALAKSHMI M. , PRASAD M. R. N. 
Published: December 2008

SUMMARY
The content and concentration of sialic acid in the testis, caput epididy-midis, cauda epididymidis and ductus deferens show changes during the transition from the prepuberal to the puberal (mature) state in the rat. The peak of sialic acid is attained in the caput epididymidis and cauda epididy-midis and ductus deferens between days 40 and 45 prior to the entry of sperms into these regions. Following the entry of sperms there is a sharp decline in sialic acid till day 60 in the caput epididymidis and ductus deferens while in the cauda epididymidis the decline in sialic acid is only transient between days 45 and 50 and is followed by sharp increase at day 60. Efferent duct ligation caused a marked decrease in content of sialic acid in the caput epididymidis only. The significance of these changes is discussed in relation to the maturation of spermatozoa.
POSSIBLE INTERACTION OF LUTEINIZING HORMONE-RELEASING FACTOR WITH OTHER HYPOTHALAMIC RELEASING FACTORS AT THE LEVEL OF THE ADENOHYPOPHYSIS
Authors: CRIGHTON D. B. , SCHNEIDER H. P. G. , McCANN S. M. 
Published: December 2008

SUMMARY
Anterior pituitary halves from adult male rats were incubated in vitro for 6 hr. in tissue culture Medium 199. Luteinizing hormone (LH) released from these glands under the influence of purified preparations of growth hormone-releasing factor (GH-RF), growth hormone-inhibiting factor (GH-IF), corticotrophin-releasing factor (C-RF) and follicle-stimulating hormone-releasing factor (FSH-RF) was determined by the ovarian ascorbic acid depletion (OAAD) assay. The effects of these factors, both alone and together with purified luteinizing hormone-releasing factor (LH-RF), were examined and compared with the response to purified LH-RF alone. While LH-RF consistently produced significant increases in LH release, none of the other factors did so, although FSH-RF showed some indication of LH-releasing activity, probably due to incomplete separation from LH-RF on the Sephadex gel filtration column used for purification. The LH released in response to LH-RF was not affected by the presence of any of the other factors. An apparent slight augmenting effect of FSH-RF could be accounted for by its contamination with LH-RF. The results are discussed in relation to the physiological mechanisms concerned in modifying LH release from the adenohypophysis.
IODINATION OF SERUM PROTEINS IN VIVO: RELATIONSHIP TO IRRADIATION AND HYPERTROPHY OF THE THYROID
Authors: TRIANTAPHYLLIDIS E. , THOMPSON B. D. , BARNABY C. F. , JASANI B. 
Published: December 2008

SUMMARY
High levels of labelled serum protein were found in rats with hypertrophied and colloid-depleted thyroids, but only after high thyroid irradiating doses of 131I. Low levels were found in rats with normal thyroids after low or high thyroid irradiating-doses of radioactive iodine. The levels in rats with hypertrophied thyroids after low thyroid-irradiating doses of 125I did not differ greatly from those in rats with normal thyroids. The mechanism of serum protein labelling is discussed and it is suggested that similar conditions may be important for the production of high levels of labelled serum protein in patients treated with radioactive iodine for functioning thyroid carcinoma.
THE METABOLISM OF [4-14C]CHOLESTEROL IN THE PRE-VIABLE HUMAN FOETUS
Authors: COUTTS J. R. T. , MACNAUGHTON M. C. 
Published: December 2008

SUMMARY
After perfusion of pre-viable human foetuses with [4-14C]cholesterol for up to 2 hr., radioactivity was widely distributed in the foetal tissues. Most of the radioactivity was recovered as unchanged cholesterol but traces of pregnenolone and 17α-hydroxypregnenolone were isolated from the liver and adrenals. No steroid conjugates were isolated although small amounts of cholesterol sulphate may have been formed and solvolysed during extraction. Judging from these results the human foetus at mid-term is unlikely to be able to synthesize progesterone from cholesterol and is dependent on a placental supply of progesterone.
OESTRIOL IN AMNIOTIC FLUID: A GAS CHROMATOGRAPHIC METHOD
Authors: BIGGS J. S. , KLOPPER A. , WILSON G. R. 
Published: December 2008

SUMMARY
A method is described for estimating oestriol in amniotic fluid. The main steps of the method are acid hydrolysis, chemical purification and methylation, chromatography on alumina columns, acetylation and estimation by gas chromatography. A radioactive internal standard is employed to correct for losses during assay. Data on the reliability of the method are given.
THE FATE OF FREE AND CONJUGATED OESTROGENS INJECTED INTO THE GRAAFIAN FOLLICLE OF EQUINES
Authors: GIORGI ELEONORA P. , ADDIS M. , COLOMBO G. 
Published: December 2008

SUMMARY
[4-14C]Oestradiol-17β, [4-14C]oestrone, Na[6,7-3H]oestradiol-17β-glucuronide and Na[6,7-3H]oestrone sulphate were injected into a Graafian follicle of two mares and a donkey after cannulation of the ovarian vein. Radioactivity was measured in follicular fluid and ovarian venous blood at different intervals after injection and in tissue and interstitial fluid at the end of the operation. Both free and conjugated oestrogens were retained to a great extent in the follicle, in the presence of constant production of endogenous oestrogens. Only a small portion of the oestrogen released from the follicle passed directly into the ovarian venous blood; a larger portion entered the effluent blood indirectly, through interstitial fluid and tissue. The conjugates, particularly the glucuronide, seemed to be excluded from the cells and accumulated in the interstitial fluid.
The role of binding of oestrogens to fluid proteins in the retention of oestrogen in follicular fluid is discussed.
THE FUNCTIONAL CAPACITY OF OVARIAN TISSUE TRANSPLANTED TO THE SPLEEN OR KIDNEY IN THE FERRET
Authors: DONOVAN B. T. 
Published: December 2008

SUMMARY
Ovarian tissue was autografted to the spleen or kidney of spayed anoestrous or oestrous ferrets to see whether inactivation of ovarian hormones occurred in the liver and to examine the feedback action of gonadal hormones on gonadotrophin secretion. Although the grafts survived in both sites as did homografts made in anoestrous females, the secretion of gonadal hormones was sufficient to cause oestrus only in a minority of animals and there was little difference in the function of grafts made to the spleen or kidney. Vulval swelling and uterine growth were caused by pellets of oestradiol inserted into the spleen so that it appears that this steroid can pass through the liver without loss of oestrogenic activity. It is concluded that little inactivation of gonadal steroids by the liver of the ferret takes place.
AN ASCENDING PATHWAY FOR RELEASE OF PROLACTIN IN THE BRAIN OF THE RABBIT
Authors: TINDAL J. S. , KNAGGS G. S. 
Published: December 2008

SUMMARY
Rabbits in pentobarbitone anaesthesia were implanted bilaterally with a pair of monopolar electrodes in the brainstem. Approximately 10 days after the operation, pseudopregnancy was induced by i.v. injection of human chorionic gonadotrophin, and 1 week later the rabbits received electrical stimulation with square-wave pulses through the implanted electrodes for two periods of 30 min. daily for 11 days. At autopsy on the following day the mammary glands were inspected for occurrence of lactogenesis and sites of electrode tips in the brain were determined histologically. Lactogenesis, indicating release of prolactin, occurred when electrical stimulation had been applied to sites in the lateral mesencephalic tegmentum and further forward in a region medio-ventral to the medial geniculate body. Passing rostrally, the pathway moved medially and then forwards in association with the extreme rostral central grey matter, and was traced as far forward as the posterior hypothalamus where sites were found close to, but not involving, the mammillo-thalamic tracts.
When compared with our previous studies on the afferent path of the milk-ejection reflex in this species, the ascending path for release of both oxytocin and prolactin appears to be the same in the mesencephalon. However, whereas the ascending path for oxytocin release bifurcates on each side into dorsal and ventral paths which reunite in the posterior hypothalamus, that for prolactin release appears to follow only the dorsal path, since stimulation of the subthalamus, through which the ventral path passes, was ineffective. It is proposed that the pathway traced in the present study represents the mesencephalic and posterior diencephalic route by which impulses initiated by the suckling stimulus attain the hypothalamus to evoke release of prolactin from the adenohypophysis.
STUDIES ON THE PRESSOR SUBSTANCES OF THE CAUDAL NEUROSECRETORY SYSTEM OF TELEOST FISH: BIOASSAY AND FRACTIONATION
Authors: CHAN D. K. O. , JONES I. CHESTER , PONNIAH S. 
Published: December 2008

SUMMARY
A method for the bioassay of the pressor substances in extracts of the urophyses of the teleost fish, Mugil auratus and Anguilla anguilla, is described. Ultracentrifugation, chromatography on Sephadex gel and treatment with trypsin and papain showed that the pressor principles are polypeptides. One fraction was protein-bound while two other fractions seem to be small molecules. Treatment with thioglycollate showed that disulphide bonds do not form an integral part of the active molecule.
The possible function of these principles in the control of the caudal circulation is discussed.
THE INFLUENCE OF THE PINEAL GLAND ON NITROGEN METABOLISM
Authors: MILCU IOANA , NANU-IONESCU LYDIA , MARCEAN RODICA , IONESCU VIOLETA 
Published: December 2008

SUMMARY
The influence of the pineal gland on protein metabolism was investigated by using a test previously devised for studying the anabolic action of growth hormone. This test consists in measuring the accumulation of urea in blood after the intravenous administration of an amino acid mixture to nephrectomized rats injected with the test substance. Like growth hormone, pineal extract significantly reduced the quantity of urea formed, suggesting an anabolic action. In contrast, in pinealectomized animals, the quantity of urea formed significantly increased when compared with controls.
ESTIMATION OF PROLACTIN AND GROWTH HORMONE LEVELS BY POLYACRYLAMIDE DISC ELECTROPHORESIS
Authors: NICOLL C. S. , PARSONS J. A. , FIORINDO R. P. , NICHOLS C. W. 
Published: December 2008

SUMMARY
A procedure for estimating rat prolactin and growth hormone (somatotrophin, STH), by measuring the optical density of the electrophoretically isolated and stained hormone bands in polyacrylamide gel columns, is described and evaluated. A simple and inexpensive densitometer is also described.
Prolactin levels in adenohypophyses and in medium from pituitary incubates were measured by electrophoresis-densitometry (ED) and by the pigeon crop-sac assay. The two methods showed a high degree of correlation. The validity of the ED method for estimating prolactin levels in adenohypophysial tissue and in incubation medium was demonstrated by comparing the prolactin content of adult male and female and of oestrogen-treated male glands and by experiments in vitro. The female pituitary contained about three times more prolactin than the male and the glands of oestrogen-treated males had levels about the same as those of females. It was also shown that the ED method could be used to demonstrate the inhibitory effects of extract of rat hypothalamic tissue on prolactin secretion in vitro by the rat pituitary. Levels of STH in adult male glands, as measured by this method, were comparable to results obtained by others using immunoassays. Propylthiouracil-induced hypothyroidism depressed the STH and prolactin levels in male rat pituitaries, in agreement with the observations of others. The stainability of the prolactin band in rat adenohypophyses was observed to decrease with time when the glands were stored on dry ice. No such change occurred in the staining characteristics of the STH band. Other aspects of the ED method are discussed, including its precision, efficiency, sensitivity, economy and utility.
RADIOACTIVE INULIN, SULPHATE AND CHLORIDE SPACES AND ELECTROLYTES IN THE THYROID GLAND OF RATS AT DIFFERENT AGES
Authors: CHOW S. Y. , WOODBURY D. M. 
Published: December 2008

SUMMARY
[14C]Inulin, 35SO42- and 36Cl- spaces, 131I- thyroid: serum (T:S) ratio, histological measurements of follicles and electrolyte content of the thyroid gland were determined in male rats 3–17 weeks of age. The thyroid [14C]inulin space of animals of different ages was not significantly different. The thyroid 35SO42- space, however, varied with age. The youngest rats had the largest 35SO42- space. Histological measurements indicated that in the thyroid follicles the epithelial cells were much thinner and the luminal volume was much larger in the younger rats than in older animals. In the older rats, the 35SO42- space was equal to the sum of [14C]inulin (stromal) and the histologically determined luminal spaces. In the younger animals, although the 35SO42- space was larger than in the older animals, it was still not large enough to equal the sum of the volumes determined by the [14C]inulin and the direct histological measurements of the lumen. This is due to the high colloid content in the follicular lumen of the young rats. The lower thyroid 131I- T:S ratio in younger rats also indicated that the thyroid gland was less active than in older animals. The volume of distribution of thyroid Cl- calculated from the chemically determined data of the plasma and of the thyroid tissue concentrations of rats of different ages was the same as that determined by 36Cl-.
THE INFLUENCE OF PITUITARY HORMONES ON THE RESPONSE OF THE SEBACEOUS GLANDS OF THE MALE RAT TO TESTOSTERONE
Authors: EBLING F. J. , EBLING ERIKA , SKINNER J. 
Published: December 2008

SUMMARY
Testosterone implants releasing about 0·2 mg./day had no effect on sebum production in hypophysectomized-castrated rats, even though treatment by a similar dose of testosterone has been shown to effect a marked increase in sebaceous activity in rats with intact pituitaries.
A preparation of porcine growth hormone, and a preparation of prolactin (luteotrophin) which had no growth hormone activity, were each capable of fully restoring the response of the sebaceous gland in hypophysectomized male rats to testosterone, though the pituitary hormones had no effect by themselves. The stimulation of sebaceous activity was measured both by the increase in sebum production and by the increased incidence of cell division in the sebaceous glands.
The responses of the preputial glands and seminal vesicles to testosterone were independent of the presence of the pituitary, and were not significantly enhanced by the hypophysial hormones.
THE RENAL HANDLING OF PHOSPHATE IN THYROID DISEASE
Authors: MALAMOS B. , SFIKAKIS P. , PANDOS P. 
Published: December 2008

SUMMARY
The fasting serum phosphate level, the tubular maximal (Tm) phosphate reabsorption and the mean renal phosphate threshold were measured in 18 hyper- and six hypothyroid patients in comparison with 11 euthyroid control subjects. A significant increase of serum inorganic phosphate, phosphate Tm and of the mean renal phosphate threshold were found in hyperthyroidism. These findings suggest an increased tubular reabsorption of phosphate in hyperthyroidism. Four main possible mechanisms of such a renal handling of phosphate in thyroid disease are briefly mentioned although their acceptance needs more direct proof.
CONVERSION OF PROLIFERATIVE ENDOMETRIUM TO SECRETORY ENDOMETRIUM BY PROGESTERONE IN ORGAN CULTURE
Authors: KOHORN E. I. , TCHAO R. 
Published: December 2008

SUMMARY
Human proliferative endometrial tissue was maintained in organ culture. Glandular cells in the fragments were stimulated to secrete by adding progesterone to the culture medium—but not by insulin, oestradiol or cortisol; insulin enhanced the effect of progesterone. With progesterone, subnuclear vacuolation appeared in the glandular cells after 2–3 days. As the culture continued, these vacuoles disappeared and secretion into the lumen occurred.
INTERACTION OF GONADAL STEROIDS AND THEIR EFFECT ON SEXUAL BEHAVIOUR IN THE RABBIT
Authors: BEYER C. , VIDAL N. , McDONALD P. G. 
Published: December 2008

SUMMARY
The effect of progestins on mating and pseudomale behaviour was studied in ovariectomized rabbits receiving 0·5 μg. oestradiol benzoate twice daily. Single injections of 0·5, 1·0 and 2·0 mg. progesterone resulted in a 50, 75 and 100% inhibition of mating behaviour respectively. In all groups maximum inhibition occurred 24 hr. after progesterone treatment. Pseudomale behaviour was also inhibited by progesterone but the response was more variable. Single injections of 8 or 20 mg. 20α-hydroxypregn-4-en-3-one did not produce a significant inhibition of either mating or pseudomale behaviour. The physiological role of these hormones in regulating sexual behaviour is discussed.
THE CONCENTRATION OF PROGESTERONE IN THE PERIPHERAL PLASMA OF THE PREGNANT EWE
Authors: BASSETT J. M. , OXBORROW TANA J. , SMITH I. D. , THORBURN G. D. 
Published: December 2008

SUMMARY
The progesterone concentration in the peripheral plasma of ewes throughout pregnancy has been determined by a protein-binding method.
Plasma progesterone concentrations during the first 50 days of pregnancy (2–3 ng./ml.) were not significantly higher than peak concentrations during the luteal phase in cycling non-pregnant ewes, but there was no decrease in the concentration 15–20 days after mating as occurs in non-pregnant ewes.
Between 50 and 120 days after mating the plasma progesterone concentration increased steadily to values 2–5 times that found in early pregnancy. These high concentrations were maintained until lambing. A decrease in progesterone concentration during the week preceding lambing was usually, but not always, observed.
Mean plasma progesterone concentrations during the last 50 days of pregnancy in ewes with twins were approximately twice those in ewes with a single foetus.
MAMMOTROPHIC AND PROLACTIN-LIKE EFFECTS OF RAT AND HUMAN PLACENTAE AND AMNIOTIC FLUID
Authors: SHANI J. , ZANBELMAN L. , KHAZEN K. , SULMAN F. G. 
Published: December 2008

SUMMARY
Mammary development in the rat during pregnancy is a continuous process beginning around the third day of pregnancy. In order to study whether mammogenesis is due to a placental stimulus, mammary development in pregnant rats was compared with that in rats with deciduomata; the latter showed no mammary development. There was no correlation between the state of the mammary gland in the rats with deciduomata and their uterine weight or development. This suggested that the placenta is a primary source of mammary development in the pregnant rat.
Rat placental homogenate, human placental extract and human amniotic fluid had mammotrophic activity in rats primed with oestradiol. The crop sac-stimulating activity of rat placental lactogen was found to be approximately 0·005 i.u. prolactin/mg. dry powder, corresponding to 0·10 i.u. prolactin/placenta. Human placental lactogen (Folrini, 95% pure) contained the equivalent of 3·3 i.u. prolactin/mg., corresponding to about 330–825 i.u./placenta. No crop sac-stimulating activity could be detected in amniotic fluid from rats or women.
RE-EXAMINATION OF THE PRESENCE OF CORTICOSTEROIDS IN TWO CYCLOSTOMES, THE ATLANTIC HAGFISH (MYXINE GLUTINOSA L.) AND THE SEA LAMPREY (PETROMYZON MARINUS L.)
Authors: WEISBART M. , IDLER D. R. 
Published: December 2008

SUMMARY
Fluorescence analyses and observations of plasma extracts on thin-layer chromatoplates including sulphuric acid chromogens failed to indicate the high concentrations of cortisol and corticosterone in Atlantic hagfish and sea lamprey reported by other workers. Double isotope derivative assays of Atlantic hagfish plasma and sea lamprey plasma failed to provide rigorous proof of the presence of these steroids.
Presumptive adrenocortical tissue from Atlantic hagfish and sea lamprey, incubated with radioactive steroids as precursors, failed to give any transformation to cortisol or corticosterone. However, sea lamprey incubations did produce 17α-hydroxyprogesterone from progesterone. No evidence was found for the presence of 17α-hydroxyprogesterone in microgram quantities in the plasma.
These findings are discussed in relation to previous studies in which high concentrations of cortisol and corticosterone were reported.
THE INTERACTION OF THE LONG-ACTING THYROID STIMULATOR (LATS) WITH THYROID TISSUE IN VITRO
Authors: SMITH B. R. 
Published: December 2008

SUMMARY
Most of the long-acting thyroid stimulator (LATS)-absorbing activity of human thyroid homogenates was shown to be in a soluble fraction containing several components including thyroglobulin, haemoglobulin and serum proteins. Salt precipitation and gel filtration studies indicated that the absorbing activity was not associated with thyroglobulin of high molecular weight, but with a 4s fraction. This 4s fraction has been shown to contain thyroid specific antigens and these may be important in LATS absorption.
BIOCHEMICAL CHANGES DURING DEVELOPMENT OF MOUSE MAMMARY TISSUE IN ORGAN CULTURE
Authors: MAYNE R. , BARRY J. M. 
Published: December 2008

SUMMARY
A study has been made of the metabolism of mammary tissue from midpregnant C3H mice in organ culture, with and without the hormones needed to induce lactogenesis in the tissue. Insulin greatly stimulated the uptake of glucose by the tissue, and the formation of labelled carbon dioxide and fatty acids from labelled glucose. The further addition of prolactin and corticosterone had little effect. Without hormones the rates of incorporation of [3H]thymidine into DNA and of [14C]uridine into RNA decreased during culture. Insulin stimulated these rates of incorporation and the further addition of prolactin stimulated them still more. Corticosterone had little effect. The rate of incorporation of [32P]orthophosphate into casein fell during culture without added hormones, while insulin, or insulin plus corticosterone, had little effect on it. Prolactin, however, caused a very marked stimulation in cultures with insulin, which was only slightly increased by the further addition of corticosterone. The stimulation of 32P incorporation due to prolactin was only evident after 12 hr. of culture. Delay in addition of prolactin by 12 hr. did not affect the response. Actinomycin D, cycloheximide and colchicine prevented the action of prolactin; hydroxyurea partly prevented it.
ANTIDIURETIC ACTIVITY AND ULTRASTRUCTURE OF THE TOAD CHOROID PLEXUS
Authors: RODRIGUEZ E. M. , HELLER H. 
Published: December 2008

SUMMARY
Acetic acid extracts of toad choroid plexuses had an antidiuretic effect in water-loaded ethanol-anaesthetized rats, whose pattern was similar to that produced by toad neural lobe extracts and by arginine vasopressin. The antidiuretic activity of the choroid plexus extracts was completely abolished by treatment with sodium thioglycollate. Antidiuretic activity per milligram choroid plexus was about four times higher in the plexus of the third ventricle than in the plexus of the fourth ventricle. The antidiuretic activity of both choroid plexuses increased progressively during the summer and autumn and reached its peak in October; it then fell to very low or undetectable levels during the middle of the winter and spring.
The choroid plexuses also showed seasonal variations in their ultrastructural organization, which might be related to the seasonal variations of their antidiuretic activity.
The origin of the substance(s) responsible for the antidiuretic activity in the choroid plexuses is discussed.