bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECTS OF FEMALE SEX HORMONES ON TISSUE REGENERATION IN THE RABBIT'S EAR
Authors: DYSON MARY , JOSEPH J. 
Published: December 2008

SUMMARY
The effects of oestradiol-17β and progesterone on tissue regeneration in the rabbit's ear were investigated. One square centimetre of tissue was excised through the whole thickness of the ear under pentobarbitone anaesthesia, and the rate of replacement, in terms of increase in surface area of the regenerated tissue, was recorded at 7-day intervals up to 49 days. The hormones were administered by subcutaneous injection five times weekly during this period. In females, oestradiol in individual doses of 10 μg/3 kg body weight stimulated regenerative growth significantly; 100 μg had no effect, and 1000 μg was inhibitory. In males, injections of 10 μg oestradiol had no significant effect on regeneration, while 100 μg was inhibitory. Progesterone stimulated regeneration in females at a dose of 100 μg/3 kg body weight, and in both males and females at 1000 μg/3 kg. Tissues were examined at 49 days for changes produced by the experimental regimes, and the effects of 17-oxosteroid excretion during the experimental period were also measured. Liver damage was produced in females by oestradiol at the 1000 μg/3 kg level and in males at the 100 μg dose; in both groups it was accompanied by loss of weight. None of the other treatments had toxic effects. The regeneration blastemata of animals treated with progesterone were better vascularized than either those of the untreated controls or of animals treated with oestradiol. The possible significance of these results is discussed.
THE ANDROGENIC POTENCY OF DIHYDROTESTOSTERONE AND TESTOSTERONE IN THE BULL, AND THE EFFECT OF GROWTH HORMONE ON THE BOVINE SEMINAL VESICLE
Authors: MANN T. , ROWSON L. E. A. , BARONOS S. , KARAGIANNIDIS A. 
Published: December 2008

SUMMARY
The androgenic effects of testosterone and dihydrotestosterone on the bovine seminal vesicles have been evaluated by (i) introducing the steroid directly into one seminal vesicle in situ, while retaining the other vesicle as a control or for the introduction of another steroid, or (ii) injecting the steroid subcutaneously into a whole animal, and examining the seminal vesicles after autopsy.
When introduced directly into a seminal vesicle dihydrotestosterone oenanthate stimulated growth and the formation of fructose and citric acid, but the magnitude of the effect was not greater than that of a similar dose of testosterone oenanthate.
When twin calves were injected subcutaneously, one with dihydrotestosterone propionate, and the other with the same dose of testosterone propionate, only the latter responded with increased output of fructose, citric acid and α-mannosidase in electro-ejaculated semen. But the seminal vesicles grew to approximately the same size in both twins.
Parenterally administered bovine growth hormone produced a sudden but transient burst of secretory activity in the seminal vesicles, resulting in the appearance of fructose and citric acid in electro-ejaculated semen.
STUDIES ON THE RELATIONSHIP BETWEEN PLASMA TESTOSTERONE LEVELS AND HUMAN SEXUAL ACTIVITY
Authors: FOX C. A. , ISMAIL A. A. A. , LOVE D. N. , KIRKHAM K. E. , LORAINE J. A. 
Published: December 2008

SUMMARY
A prolonged study relating plasma testosterone levels to coitus is reported in one male subject. Testosterone levels in samples taken during and immediately after sexual intercourse were significantly higher than those found under resting conditions. A significant difference was not apparent between testosterone measurements taken before and after orgasm, and coitus did not appear to affect plasma luteinizing hormone levels. A marked nyctohemeral rhythm was observed in testosterone levels which tended to be higher early in the day. Masturbation had no significant effect on plasma testosterone levels in seven subjects.
EFFECT OF SALT-LOADING, THIRST AND WATER-LOADING ON TRANSPORT AND TURNOVER OF NEUROHYPOPHYSIAL PROTEINS OF THE RAT
Authors: NORSTRÖM A. , SJÖSTRAND J. 
Published: December 2008

SUMMARY
The effect of salt-loading, thirst and water-loading on the axonal transport and turnover of neurohypophysial proteins in rats was investigated by measuring the radioactivity of the neural lobe proteins at various time intervals after injection of [35S]cysteine into the region of the supraoptic nucleus. Osmotic stimuli did not markedly affect the rate of transport of either the rapid or the slow phase of axonal transport of proteins. In dehydrated rats the increase of neurohypophysial radioactivity during short time intervals after isotope injection exceeded that in controls, demonstrating an increased axonal transport due to osmotic stimuli. The turnover of rapidly as well as slowly transported neurohypophysial proteins was increased after dehydration but was decreased in water-loaded rats. After water deprivation or salt-loading with 2% NaCl solution for 7 days the neural lobe neurophysin was reduced in amount by 80–90%, whereas during salt-loading with 1% NaCl solution a 20% reduction was observed on the 14th as well as the 30th day. As judged from the amount of radioactivity in posterior pituitary neurophysin in dehydrated rats it is suggested that newly synthesized rapidly transported neurophysin is rapidly released after its arrival in the neural lobe.
EFFECT OF SUCKLING AND PARTURITION ON AXONAL TRANSPORT AND TURNOVER OF NEUROHYPOPHYSIAL PROTEINS OF THE RAT
Authors: NORSTRÖM A. , SJÖSTRAND J. 
Published: December 2008

SUMMARY
The effect of suckling and parturition on axonal transport and turnover of neurohypophysial proteins was studied by determining the radioactivity in neural lobe proteins after injection of [35S]cysteine into the region of the supraoptic and paraventricular nuclei in rats.
Evidence was obtained for a lag period of more than 1 h before newly synthesized material is ready for transport along the neurohypophysial tract. Neither suckling nor parturition induced any noticeable reduction in amount of neural lobe neurophysin. The axonal transport of newly synthesized neurophysin was increased after suckling and parturition. Gel electrophoresis showed the same pattern of radiolabelling of neurohypophysial proteins as in normal female rats. The turnover of neurohypophysial proteins was increased after prolonged suckling. Differences in mode of release of oxytocin- and vasopressin-neurosecretory material are discussed. It is suggested that the neurohypophysial pool of oxytocic neurosecretory products is homogeneous.
THE EFFECT OF TESTOSTERONE ON CELL PROLIFERATION AND DIFFERENTIATION IN THE SMALL BOWEL
Authors: WRIGHT N. A. , MORLEY A. R. , APPLETON D. 
Published: December 2008

SUMMARY
The action of testosterone on the cell kinetics of the small bowel was studied in the castrated male mouse. The parameters of the cell cycle were measured using the labelled mitoses method. No difference was found between cell cycle parameters in testosterone-treated castrated animals compared with castrated controls.
Crypt cell kinetics were studied by measuring the distribution of labelled and mitotic nuclei using a computer programme. The labelling and mitotic indices were significantly raised in the testosterone-treated animals. There was also a significant upward displacement of the cut-off position in the testosterone-treated group, indicating an increase in the size of the proliferative compartment, and thus an increase in growth fraction. This change in growth fraction was confirmed by calculation from the labelled mitoses results, and is considered to be the mechanism by which testosterone stimulates cell proliferation in the small bowel of the castrated mouse. The action of testosterone on the growth fraction may constitute an important component of the general mitogenic effect of the hormone on both target and non-target tissues.
THE INHIBITION OF [35S]THIOCYANATE METABOLISM IN THE THYROID GLAND BY THYROID-STIMULATING HORMONE
Authors: BOBEK S. 
Published: December 2008

SUMMARY
When potassium [35S]thiocyanate was administered to rats, treatment with thyroid-stimulating hormone (TSH) diminished the amount of 35S per unit weight of thyroid, as well as the thyroid:plasma 35S ratio (T:P) for compounds containing 35S. Chromatographic analysis of thyroid gland homogenates and plasma showed that under the influence of TSH the 35SCN-fraction increased, while the 35SO42− fraction decreased in the thyroid. The T:P ratio calculated for both fractions confirmed the increase of the 35SCN-concentration in the thyroid. Chromatographic analysis of the plasma showed that the 35SCN− fraction in the TSH-treated animals increased gradually while it decreased in the control group.
Experiments with guinea-pig thyroid lobes in vitro agreed with the results in vivo. A significant increase of 35SCN− and a decrease in 35SO42− were found in TSH-treated thyroids after 6 h of incubation. Even clearer results were obtained by analysis of the medium. Oxidation of [35S]thiocyanate to [35S]sulphate, with a simultaneous release into the medium of the latter, took place only in the control thyroid lobes. In the TSH-treated thyroids, no changes were found in the percentage content of 35S compounds in the medium during 6 h of incubation. These results suggest that TSH inhibits the degradation of thiocyanate in the thyroid.
PATHWAYS IN THE FOREBRAIN OF THE RABBIT CONCERNED WITH THE RELEASE OF PROLACTIN
Authors: TINDAL J. S. , KNAGGS G. S. 
Published: December 2008

SUMMARY
Rabbits were implanted unilaterally with a bipolar electrode in the forebrain, and approximately 10 days later pseudopregnancy was induced by i.v. injection of human chorionic gonadotrophin. One week later the rabbits began receiving electrical stimulation with square-wave pulses through the implanted electrodes for two periods of 15 min daily for 11 days. At autopsy on the 12th day the mammary glands were inspected for the occurrence of lactogenesis and sites of electrode tips in the brain were determined histologically. In a preceding study a prolactin-release path, believed to be that normally activated by the suckling stimulus, had been traced from the mid-brain as far rostral as the posterior hypothalamus, and in the present work, lactogenesis, indicating release of prolactin, occurred after electrical stimulation of this same region in the posterior hypothalamus, between the third ventricle and the mammillo—thalamic tract. Further rostrally, effective stimulation sites were found in the medio-dorsal hypothalamus, in the farlateral hypothalamus within the medial forebrain bundle, and in the lateral and medial preoptic area. Sites extended caudally from the last area to the medial anterior hypothalamus. Passing rostrally from the lateral preoptic area, effective sites occurred in, and ventral to, the external capsule, in the claustrum and in the adjacent orbitofrontal cortex which yielded the two maximum lactogenic responses observed in the stimulated group. The role of these rostral structures, in particular the orbitofrontal cortex, is not yet clear, nor is the final mechanism mediating prolactin release, although the results suggest that the ascending pathway for prolactin release approaches the medial hypothalamus by way of the preoptic area. The presence of control electrodes in the brains of pseudopregnant rabbits was found to cause lactogenesis when their tips were in structures associated with prolactin release, as determined from the stimulated group of animals. It was concluded, therefore, that electrical stimulation may have been unnecessary in this work and that the physical irritation caused by the presence of the electrode tip in appropriate neuronal systems may be a sufficient stimulus per se to be used for tracing prolactin-release pathways in the brain.
EFFECT OF HYPOPHYSECTOMY ON CHOLESTEROL METABOLISM IN THE TESTES OF RATS AND MICE
Authors: HAFIEZ A. A. , BARTKE A. 
Published: December 2008

SUMMARY
Increased synthesis de novo of cholesterol by testes of rats and mice was found to be a contributing factor in the increased testicular cholesterol content after hypophysectomy. This was shown by increased [1-14C]acetate incorporation in vitro into free and esterified cholesterol by testicular tissue from rats and mice hypophysectomized 3 weeks earlier, as compared with intact controls.
In mice, testicular cholesterol content was significantly increased 1 day after hypophysectomy at which time there was no change in the testis weight. Three weeks after the operation there was a significant decrease in testis weight and a significant increase in the concentration of free, esterified and total cholesterol as well as in the percentage of esterified fraction. These changes were even more pronounced 1 month later.
ULTRASTRUCTURAL CHANGES IN THE ADENOHYPOPHYSIS OF METYRAPONE-TREATED RABBITS
Authors: CAMERON E. , FOSTER C. L. 
Published: December 2008

SUMMARY
Metyrapone was used to increase the production of adrenocorticotrophin in the rabbit and it was considered likely that the cells of the adenohypophysis showing ultrastructural features indicative of heightened secretory activity would be those producing the hormone. A cell type fulfilling these conditions was observed to have the following characteristics: polygonal shape, secretory granules of approximately 150 nm in diameter, distended cisternae of the rough endoplasmic reticulum, hypertrophied Golgi areas, long sinuous mitochondria and numerous free ribosomes, often arranged in clusters. A second type of cell with larger granules sparsely distributed is also described and its significance briefly discussed. The adrenals of several of the experimental animals were greatly hypertrophied but the drug had no observable effect either on the thyroid or the gonads.
EFFECT OF LUTEINIZING HORMONE ANTISERUM ON PROGESTERONE AND 20α-DIHYDROPROGESTERONE SECRETION IN THE PREGNANT RAT
Authors: MOUDGAL N. R. , BEHRMAN H. R. , GREEP R. O. 
Published: December 2008

SUMMARY
The effect of a single injection of luteinizing hormone (LH) antiserum on ovarian progesterone and 20α-dihydroprogesterone in day-8 and day-15 pregnant rats was studied. Within 24 h of an injection of LH antiserum, progesterone secretion was reduced by 80% in day-8 and by 25% in day-15 pregnant rats. The 20α-dihydroprogesterone levels after antiserum treatment were markedly increased in rats which were 8 days pregnant but reduced in rats which were 15 days pregnant. The free cholesterol content of the ovary did not change after antiserum injection but the cholesteryl ester content markedly increased. It is thus apparent that neutralization of endogenous LH resulted in a significant reduction in the progesterone secretion of the corpus luteum of the pregnant rat. The significance of these results is discussed.
STUDIES WITH ANTISERA TO LUTEINIZING HORMONE IN VIVO AND IN VITRO ON LUTEAL STEROIDOGENESIS AND ENZYME REGULATION OF CHOLESTERYL ESTER TURNOVER IN RATS
Authors: BEHRMAN H. R. , MOUDGAL N. R. , GREEP R. O. 
Published: December 2008

SUMMARY
The effect of antiserum to luteinizing hormone (LH) on progesterone and 20α-dihydroprogesterone output and on the enzymes regulating luteal cholesteryl ester turnover was measured in pseudopregnant rats to provide information on the role of LH in regulating luteal function. Progesterone synthesis was reduced when antiserum was added directly to an incubation system of luteinized ovarian slices from animals which had received intravenous saline or 10 μg LH. Steroidogenesis was stimulated in vitro when LH was previously given in vivo, and also on incubating luteinized ovaries from animals treated with antiserum. Treatment in vivo with antiserum alone, however, increased progesterone and 20α-dihydroprogesterone synthesis in vitro but this appeared to be an effect of incubation since in a separate experiment peripheral serum levels of both progesterone and 20α-dihydroprogesterone were reduced after antiserum treatment. Ovarian levels of cholesteryl ester and cholesterol were increased after antiserum treatment in vivo. The level of ovarian cholesteryl esterase was reduced to only 10% of the control level 24 h after antiserum treatment and in this period the level of cholesteryl ester synthetase increased 1·5 times. From these results LH appears to play a direct role in regulating the activity of enzymes controlling cholesteryl ester turnover and thereby regulates the availability of cholesterol for conversion to steroids.
THE EFFECTS OF HYPOPHYSECTOMY ON THE METABOLISM OF ADRENAL STEROIDS IN THE PIGEON (COLUMBA LIVIA)
Authors: CHAN MO YIN , BRADLEY E. L. , HOLMES W. N. 
Published: December 2008

SUMMARY
The distribution and disappearance of radioactivity after the intravenous administration of [1,2-3H]corticosterone and [1,2-3H]aldosterone to the pigeon were studied according to one- and two-compartment model systems. The volume of distribution (AVD) of the total and methylene chlorideextractable radioactivity in the plasma of hypophysectomized pigeons injected with labelled corticosterone was significantly increased. Also the biological half-life (T½) of each radioactive fraction in plasma was significantly prolonged. No significant change in the metabolic clearance rate (MCR) of labelled corticosterone was observed in the hypophysectomized pigeon.
The AVD of the total and methylene chloride-extractable tritium in the plasma of the hypophysectomized pigeon injected with labelled aldosterone was unchanged but the T½ of both plasma fractions was significantly prolonged. The estimated MCR of labelled aldosterone was significantly diminished.
The concentration of total fluorogenic corticosteroid in plasma from the chronically hypophysectomized pigeon was reduced to one-third of that in the sham-operated bird, and corticotrophin-replacement therapy restored the concentration to normal. After hypophysectomy, the plasma corticosterone concentration was reduced to 20% of the concentration in the sham-operated birds, and replacement therapy with corticotrophin again restored the plasma levels to normal. Estimation of the endogenous corticosterone secretory rates indicated that chronic hypophysectomy was accompanied by a decline commensurate with the reduction in the plasma corticosterone concentration.
THE EFFECT OF TESTOSTERONE AND TESTOSTERONE METABOLITES ON THE FINE STRUCTURE OF THE RAT PROSTATE GLAND IN ORGAN CULTURE
Authors: GITTINGER J. W. , LASNITZKI ILSE 
Published: December 2008

SUMMARY
The action of testosterone and its metabolites, dihydrotestosterone and 3β-androstanediol on the fine structure of the rat ventral prostate gland in organ culture was investigated. In intact glands before explantation the epithelial cytoplasm showed a system of membrane-bound ergastoplasmic channels studded with ribosomes, a discrete Golgi body, associated with secretory vacuoles and microvilli projecting into the lumen.
In explants grown in non-supplemented medium the epithelium underwent a severe regression. The ergastoplasm collapsed and was fragmented and there was no discrete Golgi body. Microvilli were absent and a number of electron-dense bodies interpreted as lysosomes were scattered throughout the cytoplasm.
In explants grown in the presence of testosterone, dihydrotestosterone and 3β-androstanediol the fine structure was similar to that in the intact gland. Ergastoplasm and Golgi apparatus were well maintained, secretory vacuoles could be observed and the microvilli resembled in size and number those of the normal organ.
In hyperplastic areas of explants treated with dihydrotestosterone, the maintenance of the ergastoplasm was less complete but the Golgi zone and microvilli were well preserved.
In explants treated with testosterone or dihydrotestosterone, nucleolar bodies were observed in many nuclei of epithelium and stroma.
The effects of the steroids on the fine structure of the gland confirm those seen at the light microscopic level and support the suggestion that the action of testosterone is mediated through its metabolites.
THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR BOVINE NEUROPHYSIN
Authors: MARTIN MARION J. , CHARD T. , LANDON J. 
Published: December 2008

SUMMARY
A radioimmunoassay for bovine neurophysin is described. The assay has a lower limit of detection of approximately 0·5 ng/ml. Bovine neurophysin extracted and purified from acetone-dried posterior pituitary lobe powder was used for standardization, radio-iodination and immunization of rabbits. Some anti-neurophysin sera were also obtained from human subjects treated with Pitressin. Most of the antisera tested did not readily distinguish between the different neurophysin components isolated from bovine neurohypophysial tissue. The antisera cross-reacted with material extracted from whole pituitaries of a number of mammalian species, including man, pig, sheep, guinea-pig and rat, but not with the pituitary peptides from the cod or dogfish, or the egret. Other pituitary peptides, including oxytocin, vasopressin, corticotrophin, growth hormone and luteinizing hormone, did not interfere with the assay.
INSULIN RELEASE FROM HUMAN FOETAL PANCREAS IN RESPONSE TO GLUCOSE, LEUCINE AND ARGININE
Authors: MILNER R. D. G. , ASHWORTH M. A. , BARSON A. J. 
Published: December 2008

SUMMARY
Pieces of pancreas from human foetuses of 14–24 weeks gestational age and weighing between 50 and 625 g were incubated in vitro. Insulin release was studied under control conditions and in media supplemented with glucose (3 mg/ml), leucine (5 mmol/1) or arginine (5 mmol/1). Glucose never caused a significant rise in insulin release from the pancreas. The failure of mannoheptulose (3 mg/ml) and 2-deoxyglucose (3 mg/ml) to suppress basal insulin release in a glucose-free medium indicated that basal insulin release was not governed by the liberation of glucose from glycogen in the exocrine pancreas. Arginine stimulated insulin release in four experiments using pancreas from foetuses weighing more than 200 g, but failed to cause insulin release from the pancreas of foetuses weighing less than 200 g in three experiments. Leucine consistently stimulated insulin release from the pancreas of foetuses of less than 200 g body weight but was only variably effective in causing insulin release from pancreas of foetuses weighing more than 200 g. The experimental results illustrate the development of different mechanisms for the release of insulin from the human foetal β cell.
THE EFFECT OF METYRAPONE ON CORTICOTROPHIN SECRETION
Authors: DONALD R. A. , ESPINER E. A. , BEAVEN D. W. 
Published: December 2008

SUMMARY
The plasma immunoreactive corticotrophin (ACTH) response to metyrapone (1 g orally at 08.00 h, and 6 hourly thereafter for 48 h) was analysed in 20 patients with a normal oxogenic steroid response. A greater than threefold rise in the mean plasma ACTH concentration was observed within 24 h. The mean plasma ACTH level at 08.00 h on the 2nd day of the test was significantly higher than the mean level at 16.00 h, indicating that the diurnal rhythm in ACTH release persists despite metyrapone administration. The degree of rhythmicity, as assessed by the ratio of the means of the 08.00 and 16.00 h ACTH values on the 2nd day of metyrapone administration, was comparable to, but slightly less than that observed in untreated normal controls.
The ACTH response to reduction of circulating cortisol levels was also studied by interrupting steroid replacement therapy for 24 h in eight patients with adrenal disease. The observed increase in plasma ACTH was more variable than that after metyrapone, the rapidity of the ACTH rise possibly being influenced by the details of previous replacement therapy and the severity of the adrenal disease.
There was no significant difference in the plasma ACTH response to metyrapone and insulin-induced hypoglycaemia in 13 patients whose pituitary function had been assessed by each of these procedures.