bluuebunny/crossref_metadata_2025 huggingface dataset:
CONCENTRATIONS OF OESTROGEN AND PROGESTERONE IN THE PLASMA OF NON-PREGNANT, PREGNANT AND LACTATING GUINEA-PIGS
Authors: CHALLIS J. R. G. , HEAP R. B. , ILLINGWORTH DOREEN V.
Published: December 2008

A competitive protein-binding assay of progesterone and a radioimmunoassay of total unconjugated oestrogens were evaluated and employed in the measurement of these steroids in the plasma of guinea-pigs at different times during the reproductive cycle. Production rates (PR) were calculated from the product of the endogenous steroid concentration and its metabolic clearance rate. During the oestrous cycle, plasma progesterone levels rose from undetectable levels at the time of ovulation to 2·8 ± 0·33 (s.e.m.) ng/ml 5 days later; PR was 0·26 mg/day. During pregnancy, plasma progesterone concentrations in post-partum mated guinea-pigs rose from 15 ng/ml at day 15 post coitum (p.c.) (PR, 0·65 mg/day) to a peak value of 329 ± 14 ng/ml by days 30 to 45. The concentration fell 51–55 days p.c. (160 ± 14·7 ng/ml), but rose before parturition to 258 ± 22 ng/ml. After day 20 p.c., PR was 1·24 ± 0·3 mg/day. After parturition, plasma progesterone levels fell rapidly and during lactation were about 10 ng/ml (PR, 0·4 mg/day).

Total unconjugated oestrogens in arterial plasma were not detected in early pregnancy, but rose from values of 12·8 ± 1·9 pg/ml (days 31–35) to 31·0 ± 5·2 pg/ml (days 56–60). There was a slight fall before, and a rapid one after parturition. The ratio of progesterone to oestrogen in plasma fell during pregnancy and reached its lowest values between days 55 and 60.
ESTIMATION OF URINARY GONADOTROPHINS BY BIOASSAY AND RADIOIMMUNOASSAY
Authors: BUTT W. R. , LYNCH S. S.
Published: December 2008

The results of the application of a solid-phase radioimmunoassay for follicle-stimulating hormone (FSH) to 376 24-h urine specimens assayed routinely by the ovarian augmentation method for FSH, and 663 24-h urine specimens assayed routinely by the uterine weight method for total gonadotrophins, are presented. The correlations between the immunoassay and the bioassays were significant and about 70% of the results were in the same categories whichever method was used. The use of the radioimmunoassay for the clinical assessment of pituitary—gonadal function is discussed.
ACUTE EFFECTS OF SYNTHETIC PORCINE CALCITONINS ON THE RENAL EXCRETION OF MAGNESIUM, INORGANIC PHOSPHATE, SODIUM AND POTASSIUM
Authors: NIELSEN S. PORS , BUCHANAN-LEE B. , MATTHEWS E. W. , MOSELEY J. M. , WILLIAMS C. C.
Published: December 2008

Synthetic porcine calcitonin (α-calcitonin) and its methionine-sulphoxide derivative (β-calcitonin) were given by intravenous infusion to conscious male rats. α-Calcitonin inactivated by performic acid oxidation was used as a control.

Microgram doses of α-calcitonin produced a dose-dependent decrease in the renal excretion of magnesium. The effect was not due to a secondary release of parathyroid hormone since it was also seen in parathyroidectomized animals.

A marked increase in the renal excretion of inorganic phosphate, sodium and potassium preceded the change in magnesium excretion in parathyroidectomized rats. It is concluded that the phosphaturia and natriuresis previously described after administration of extracted calcitonin preparations are true effects of the hormone.

The effect of β-calcitonin was indistinguishable from that of α-calcitonin.
EFFECTS OF TESTOSTERONE ON GLYCOSAMINOGLYCANS IN THE PROSTATE, SEMINAL VESICLES AND SALIVARY GLANDS OF THE RAT
Authors: KOFOED J. A. , HOUSSAY A. B. , TOCCI A. A. , CURBELO H. M. , GAMPER C. H.
Published: December 2008

The effects of castration, and of the daily administration of 100 or 300 μg testosterone propionate (TP) for 1 month to castrated animals, on the glycosaminoglycans of the ventral prostate, seminal vesicles and salivary glands, were studied in male white rats.

Castration produced atrophy of the ventral prostate and seminal vesicles together with increased concentration of uronic acid, and atrophy of the submaxillary glands together with decreased uronic acid concentration. The administration of TP to castrated animals produced opposite effects. No changes in weight or in uronic acid concentration were found in the parotid and retrolingual glands. Fractionation on cellulose microcolumns showed that the changes in uronic acid concentration were due to changes in fraction 1 (glycoproteins) in the submaxillary glands, in fractions 2 (hyaluronic acid) and 3 (heparitin sulphate) in the seminal vesicles, and in all the chromatographic fractions in the ventral prostate.
SITE OF DEHYDROEPIANDROSTERONE SULPHATE BIOSYNTHESIS IN THE ADRENAL GLAND OF THE PREVIABLE FOETUS
Authors: COOKE B. A. , TAYLOR PATRICIA D.
Published: December 2008

The localization of enzymes required for dehydroepiandrosterone sulphate (DHAS) biosynthesis from pregnenolone in human foetal adrenal glands was investigated using a microtechnique to obtain serial tissue sections through the glands.

Both zones of the adrenal glands converted pregnenolone to pregnenolone sulphate and to 17α-hydroxypregnenolone, dehydroepiandrosterone and their sulphates. A higher conversion to the steroid sulphates was found in the foetal compared with the adult zone tissue incubations. In two experiments, the highest conversion to DHAS occurred with tissue from the foetaladult border zone. The relative amounts of the steroids formed during incubation with whole gland homogenates were similar to those formed in the incubations of the foetal zone.
THE ESTIMATION OF PLASMA 11-DEOXYCORTICOSTERONE IN MAN USING GAS-LIQUID CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION
Authors: WILSON A. , FRASER R.
Published: December 2008

A method of estimating the peripheral plasma concentration of 11-deoxycorticosterone (DOC) in man by means of gas-liquid chromatography with electron capture detection is described. Purification requirements for samples and chromatographic media have been simplified by the use of a detector bypass valve which reduces the risk of detector contamination. For this reason the method is relatively short. There was no measurable blank using either plasma from an adrenalectomized subject or water. The normal range was found to lie between 4·1 and 17·2 ng/100 ml (mean 9·8). Dexamethasone administration to one subject resulted in a subnormal plasma DOC concentration.
THE EFFECTS OF DEXAMETHASONE AND ANDROGENS ON SEXUAL RECEPTIVITY OF FEMALE RHESUS MONKEYS
Authors: EVERITT B. J. , HERBERT J.
Published: December 2008

The effect of dexamethasone, given either alone or together with testosterone propionate or androstenedione, was studied in nine female rhesus monkeys (paired with three males) by making quantitative observations on behaviour in the laboratory.

Dexamethasone (0·5 mg/kg/day) given to oestrogen-treated ovariectomized female monkeys made them sexually unreceptive, and there was an associated decline in the level of the male's mounting activity. Testosterone propionate (100 or 200 μg/day) reversed completely the effects of dexamethasone on sexual behaviour. Androstenedione (100, 200 or 400 μg/day) had similar, but less marked, effects whereas cortisol (10 mg/day) or progesterone (100, 200 or 500 μg/day) were ineffective. Treating a female with testosterone prevented dexamethasone from reducing sexual receptivity. Parallel determinations of urinary free cortisol showed that the dexamethasone had suppressed the secretory activity of the adrenal cortex. There were no consistent changes, under any treatment, in the females' vaginal epithelia, sexual skins or clitorides, or in their water or electrolyte metabolism.

These findings indicate that adrenal androgens regulate sexual receptivity in these female primates, probably by an action on the central nervous system.
A PERFUSED TELEOSTEAN GILL PREPARATION: VASCULAR ACTIONS OF NEUROHYPOPHYSIAL HORMONES AND CATECHOLAMINES
Authors: RANKIN J. C. , MAETZ J.
Published: December 2008

When isolated eel gills were perfused under conditions resembling, as closely as possible, those found in vivo and under constant pressure, neurohypophysial hormones decreased and catecholamines increased the rate of flow of perfusate, the latter response being mediated by β-adrenergic receptors. When the Ringer solution was not filtered before use, flow rates rapidly declined and 10−5 m-adrenaline or noradrenaline was required to maintain constant flow. Under these conditions, 10−14 m-isotocin or 10−13 m-arginine vasotocin (AVT) produced vasoconstriction. When the Ringer solution was filtered through a 0·22 μm Millipore filter before use, constant high flow rates could be maintained in the absence of catecholamines. Noradrenaline increased the flow rate at concentrations of down to 10−9 mol/l, adrenaline being slightly less active when filtered Ringer solution was used. However, the sensitivity to neurohypophysial hormones was considerably reduced, 10−11 to 10−10 m-isotocin and 5 × 10−11 to 5 × 10−10 m-AVT being the lowest concentrations producing vasoconstriction.

No difference in sensitivity to neurohypophysial hormones or catecholamines was observed between gills from seawater adapted or freshwater adapted gills. The results are discussed in relation to the alternative pathways of blood flow through the gills.
LIPID METABOLISM OF THE RAT UTERUS AFTER MATING
Authors: BEALL J. R. , WERTHESSEN N. T.
Published: December 2008

In this study of lipid metabolism of the rat uterus during early pregnancy, lipids were extracted after incubation with [1,2-14C]acetate or after its administration in vivo. The results indicated that the synthesis and concentration of triglyceride increased with time after mating. Triglyceride accumulated in uterine tissue before implantation and was depleted in tissue from implantation areas by day 7. Synthesis of fatty acid increased with time after mating, as did the concentration of various lipids other than cholesterol in the free sterol fraction. Supporting the concept that lipids are necessary during early embryonic development, the results suggest that the rat utilizes endometrial fatty acid esterified to triglyceride. No trends related to time were seen in the rate of synthesis nor in the concentration of sterol ester or free fatty acid; hence, specific concentrations of these lipids are probably not necessary for embryonic development during early pregnancy.
THE EFFECTS OF FEMALE SEX HORMONES ON TISSUE REGENERATION IN THE RABBIT'S EAR
Authors: DYSON MARY , JOSEPH J.
Published: December 2008

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
ADENYL CYCLASE ACTIVITY IN THE MOUSE THYROID GLAND
Authors: KENDALL-TAYLOR PAT
Published: December 2008

The activation of adenyl cyclase in intact mouse thyroid glands was measured by the conversion of [3H]ATP to [3H]cyclic AMP.

Untreated serum had an inhibitory effect. Human thyroid-stimulating hormone (TSH) and γG-globulin prepared from serum containing the long-acting thyroid stimulator (LATS), activated adenyl cyclase and the log-dose—response relationship did not deviate from parallelism. The rate of activation by LATS was slower and the peak response was delayed, compared with the response to TSH. The possible significance of this is discussed.

Other hormones and neurotransmitters examined had no effect on thyroidal adenyl cyclase.
PLASMA AND PITUITARY LUTEINIZING HORMONE AND PERIPHERAL PLASMA OESTRADIOL CONCENTRATIONS IN THE NORMAL OESTROUS CYCLE OF THE RAT AND AFTER EXPERIMENTAL MANIPULATION OF THE CYCLE
Authors: NAFTOLIN F. , BROWN-GRANT K. , CORKER C. S.
Published: December 2008

Plasma and pituitary luteinizing hormone (LH) concentrations were measured by radioimmunoassay at different stages of the normal 4- and 5-day oestrous cycle of rats. Plasma levels were low except between the afternoon of pro-oestrus and the morning of oestrus when levels were high but variable. Pituitary LH content and concentration were less consistent but averaged values showed a steady rise from a low level after ovulation to a peak on the afternoon of pro-oestrus, and a rapid fall that evening when plasma levels rose rapidly.

No significant differences were observed in plasma LH between 4- and 5-day cycles; in particular there was no reduction at metoestrus or dioestrus-1 or increase on the evening of dioestrus-2. Plasma oestradiol was already high on the morning of dioestrus-2 in some rats and in all rats by that evening. On the morning of pro-oestrus in the 5-day cycle, plasma oestradiol was still high but somewhat lower than at the corresponding stage in the 4-day cycle.

Blocking ovulation by administration of sodium pentobarbitone at prooestrus in a 4-day cycle prevented the rise in plasma LH and the fall in pituitary content. Blocking generally failed in animals whose plasma LH had reached the level of 20 ng/ml or more at the time of injection. Plasma oestradiol levels on the morning of the expected day of oestrus were higher than normal in animals in which ovulation was blocked by pentobarbitone but were below pro-oestrous values. In the anovulatory state induced by exposure to constant light no major increase in plasma LH was detected after 24 days of illumination or after 3 months exposure. Animals rendered anovulatory by injection of testosterone propionate on the 4th day of postnatal life had low plasma LH levels as adults. All three groups had a low pituitary LH content. The animals exposed to long-term light and those treated with androgen generally had plasma oestradiol concentrations below the peak levels seen on the morning of pro-oestrus in the normal cycle.
INFLUENCE OF THE REPRODUCTIVE STATE AT THE TIME OF OPERATION ON THE EARLY RESPONSE TO OVARIECTOMY IN THE RAT
Authors: TAPPER C. M. , NAFTOLIN F. , BROWN-GRANT K.
Published: December 2008

The changes in plasma luteinizing hormone (LH) concentration during the first few days after ovariectomy in the rat differ according to the stage of the cycle at which the operation is performed. When carried out at oestrus there was no increase in LH concentration in the first 4 days. After operation at metoestrus the concentration was increased at 3 days but not earlier. Ovariectomy at dioestrus resulted in an immediate increase after 8 h, a subsequent fall, though not to basal levels, and a fairly steady rise thereafter. Ovariectomy at pro-oestrus produced a very large initial rise in plasma LH which probably represents an accelerated release of the ovulatory surge of LH rather than a specific response to ovariectomy. At 24 h after ovariectomy at pro-oestrus levels were below normal and did not increase again for a further 3 days. In contrast, male rats showed a rapid and sustained rise in plasma LH concentration after castration. It is suggested that the different patterns seen in the female may be related to the time that elapsed since the hypothalamo—pituitary system was exposed to high levels of circulating oestradiol. The changes in plasma LH concentration observed after ovariectomy in neonatally androgen-treated rats, rats in persistent oestrus due to exposure to constant light, and rats in early pregnancy are consistent with this hypothesis. Differing responses to the administration of sodium pentobarbitone between male and female rats even 21 days after gonadectomy suggest that there may also be differences in this negative feedback system between the two sexes that are independent of the nature of the gonadal steroid secreted.
ULTRASTRUCTURAL AND HISTOCHEMICAL STUDIES ON THE TESTIS OF THE RIVER LAMPREY, LAMPETRA FLUVIATILIS (L.)
Authors: BARNES K. , HARDISTY M. W.
Published: December 2008

The structure of interstitial cells and the cells of the lobule wall was studied in the lamprey testis throughout the period of sexual maturation. In the course of their secretory cycle the interstitial cells showed the usual characteristics of vertebrate steroidogenic tissues; a well-developed agranular reticulum, mitochondria with a dense matrix and tubular cristae, and lipid inclusions. Similar characteristics were also seen in the cells of the lobule wall in the period immediately preceding spermiation. In the interstitial cells, hydroxysteroid dehydrogenase (HSD) activity reached a maximum in late January and February, in advance of the development of the secondary sex characteristics, and was correlated with the abundance of interstitial lipid. After hypophysectomy, no changes were detected in the numbers or volume of interstitial tissue, and HSD activity was apparently unaffected. Characteristic multivesiculate bodies were not observed in the cells of the lobule wall in hypophysectomized animals.
THE RETICULO—HYPOTHALAMIC PATHWAY CONTROLLING THE RELEASE OF OXYTOCIN IN THE EWE
Authors: RICHARD Ph.
Published: December 2008

The pathways of the milk-ejection reflex in the ewe have been described at the spinal and mesencephalic levels (Richard, 1970; Richard, Urban & Denamur, 1970). The present paper describes the pathways followed by impulses of mammary and vaginal origin between the mesencephalic reticular formation and the neurohypophysis.

In the anaesthetized ewe the thalamus is not necessary for the transfer of impulses to the neurohypophysis as shown by studying the electrical activities evoked in the pituitary stalk by mammary or vaginal stimulation. These impulses follow a subthalamic pathway through the medial forebrain bundle. In conscious ewes small areas of coagulations in the pathways did not block the milk-ejection reflex during milking because the fibres are diffuse at all levels of the central nervous system. Larger lesions result in non-specific effects which interrupt milk secretion.

Supra-diencephalic structures are not necessary for the milk-ejection reflex.
DISTRIBUTION OF 5α-DIHYDROTESTOSTERONE IN THE EPIDIDYMIS OF BULL AND BOAR, AND ITS CONCENTRATION IN RAT EPIDIDYMIS AFTER LIGATION OF EFFERENT TESTICULAR DUCTS, CASTRATION AND UNILATERAL GONADECTOMY
Authors: AAFJES J. H. , VREEBURG J. Th. M.
Published: December 2008

5α-Dihydrotestosterone concentrations were appreciably higher than testosterone concentrations in the epididymides of both a bull and a boar. The highest concentration of 5α-dihydrotestosterone was found in the heads of these organs. When tritiated testosterone was injected into a castrated rat most of the radioactivity recovered from the epididymis was present as 5α-dihydrotestosterone. Recrystallization confirmed the identity of this compound. In a separate experiment the concentration of 5α-dihydrotestosterone in the epididymis after castration decreased to unmeasurable amounts in about 27 h. This was not the case when only one testis was removed or when testosterone was injected after castration. Ligation of the efferent ducts of a testis on one side resulted in a lowered 5α-dihydrotestosteron concentration in the epididymis of that side. This finding suggests a possible role of spermatozoa in the metabolism of testosterone to 5α-dihydrotestosterone. However, the presence of 5α-dihydrotestosterone in the epididymis of very young rats without spermatozoa showed that spermatozoa are not required for this metabolism.
THE ROLE OF PROLACTIN IN THE REGULATION OF TESTIS FUNCTION: THE SYNERGISTIC EFFECTS OF PROLACTIN AND LUTEINIZING HORMONE ON THE INCORPORATION OF [1-14C]ACETATE INTO TESTOSTERONE AND CHOLESTEROL BY TESTES FROM HYPOPHYSECTOMIZED RATS IN VITRO
Authors: HAFIEZ A. A. , BARTKE A. , LLOYD C. W.
Published: December 2008

Hypophysectomized adult male rats were treated twice daily for 3½ days with 0·9% NaCl solution, 200 μg ovine prolactin, 5 μg ovine luteinizing hormone (LH), or 200 μg prolactin +5 μg LH, starting 18 days after the operation. Minced testes from these animals were incubated in Krebs—Ringer bicarbonate buffer containing [1-14C]acetate for 3 h at 37 °C. The conversion of acetate into testosterone was calculated. It was not changed by prolactin treatment, was increased by LH (P < 0·01), and further increased by prolactin + LH (P < 0·01) to approximately the level observed in intact adult controls. The amount of testosterone in some of the incubates was measured by gas liquid chromatography. It was not changed in prolactin-treated animals and was increased in LH-treated animals (P < 0·02 compared with hypophysectomized controls). Treatment with prolactin+LH resulted in an increase in testosterone above that after treatment with LH alone (P < 0·01) and to a value similar to that in intact adult males. The incorporation of acetate into esterified cholesterol was decreased (P < 0·05) in groups treated with LH or prolactin + LH in which testosterone synthesis was increased. The incorporation of acetate into free cholesterol was not changed by any of the treatments. These results demonstrate synergistic action of prolactin and LH on the synthesis of testosterone in vitro confirming our earlier suggestions.
HUMAN OVARIAN RESPONSE TO GONADOTROPHINS WITH DIFFERENT RATIOS OF FOLLICLE-STIMULATING HORMONE: LUTEINIZING HORMONE ASSESSED BY DIFFERENT PARAMETERS
Authors: BERTRAND P. V. , COLEMAN J. R. , CROOKE A. C. , MACNAUGHTON M. C. , MILLS I. H.
Published: December 2008

Eight women with secondary amenorrhoea were treated, four at each of two centres. They were each given four preparations of gonadotrophin having different ratios of follicle-stimulating hormone (FSH) to luteinizing hormone (LH) and the order of treatment with the preparations was determined at each centre by a latin square design. At the completion of these treatments each patient received a fifth preparation of gonadotrophin. The dosage of FSH was determined for each woman by a previous sensitivity test and remained constant for each of her 5 months of treatment. Each gonadotrophin preparation was given in approximately equal daily injections on days 1, 2 and 3 of each course of treatment and was invariably followed by a single injection of 12000 i.u. human chorionic gonadotrophin on the 10th day. Treatment was assessed by the measurement of the excretion of oestriol and pregnanediol, by vaginal cytology, by the degree of ferning of cervical mucus and by the basal body temperature (BBT). The administration of gonadotrophin with a ratio of FSH:LH < 1·0 produced a greater excretion of oestriol than gonadotrophin with a ratio of FSH:LH > 4·0. There was no significant loss of sensitivity to treatment with time. The karyopyknotic index was correlated with the excretion of oestriol but neither was of use in predicting the other because of the wide scatter. There was no correlation between the degree of ferning and the excretion of oestriol. Assessments of ovulation by the pregnanediol response and by the BBT were in good agreement. These results are discussed.
QUANTIFICATION OF ULTRASTRUCTURAL CHANGES IN THE 'MELANOCYTE-STIMULATING HORMONE CELL' OF THE PARS INTERMEDIA OF THE PITUITARY OF XENOPUS LAEVIS, PRODUCED BY CHANGE OF BACKGROUND COLOUR
Authors: WEATHERHEAD B. , WHUR P.
Published: December 2008

The fact that the transfer of amphibians between black and white backgrounds causes the 'melanocyte-stimulating hormone (MSH) cells' of the pars intermedia of the pituitary to undergo considerable morphological change has been established for some time. The application of morphometric techniques to the 'MSH cells' of Xenopus has permitted the quantitative analysis of these changes at the ultrastructural level. Of the nine classes of organelle selected for analysis in these cells, three, namely nucleus, plasma membrane and dense bodies, showed no statistically significant changes. The remaining classes of organelle all showed significant changes in the percentage of the total cell volume that they occupied, although not all the organelles changed at the same rate. Transfer of animals from a white to a black background for up to 12 days was associated with increase in the percent volume of rough endoplasmic reticulum, Golgi membranes, Golgi granules and mitochondria and with a decrease in the percent volume of the fibrous granules. Return of animals to a white background after 6 days on a black background produced a reversal of the above changes with return to, or close to, white background (control) levels. This quantitative ultrastructural approach also highlights discrepancies in both the rate and magnitude of the changes in some of the organelles and related non-morphological parameters previously reported, e.g. the size of the rough endoplasmic reticulum and the rate of incorporation of labelled amino acid into protein; or the numbers of fibrous granules and the levels of detectable pituitary MSH. Some possible interpretations of these discrepancies are discussed.