bluuebunny/crossref_metadata_2025_split huggingface dataset:
HORMONE-INDUCED ACTIVATION OF TARGET-SPECIFIC LYSOSOMES: ACUTE TRANSLOCATION TO THE NUCLEUS AFTER ADMINISTRATION OF GONADAL HORMONES IN VIVO
Authors: SZEGO CLARA M. , SEELER BARBARA J. 
Published: December 2008

SUMMARY
Recent evidence from these laboratories has implicated the primary lysosomal population of specific target cells in the selective reception of steroid hormones at the cell periphery. This phenomenon was shown to be associated with covert labilization of the lysosomal bounding membrane. It has now been demonstrated that this interaction with trophic hormones results in rapid migration of lysosomes to a perinuclear position. Suspensions of nuclei were isolated from preputial glands of ovariectomized rats within short intervals after administration of gonadal hormone in vivo. Identification of cellular organelles by ultraviolet fluorescence microscopy was carried out on preparations subjected to intravital staining in vitro with acridine orange. Lysosomes were present in high concentrations in nuclear fractions of preputial glands from animals pretreated with oestradiol-17β, diethylstilboestrol, or testosterone, and essentially absent in preparations obtained from animals injected with oestradiol-17α or control solution. The response could be detected within 1 min of hormone administration, was obtained with as little as 0·1 μg hormone/100 g body wt, and was not observed in preparations from lung tissue. In the early stages of hormonal activation, lysosomes in preputial gland preparations formed adherent perinuclear clusters and appeared relatively intact. However, lysosome fragmentation and dissolution rapidly ensued and was accompanied by the appearance of polynuclear—multilysosomal aggregates. Concomitantly, isolated lysosome preparations subjected to enzymatic analyses revealed increased release from the particle-bound form of hydrolytic enzymes characteristic of these organelles. Progressive nuclear metachromasy was also observed after administration of the active hormones, suggesting the breakdown of macromolecules which yield products with enhanced capacity for binding acridine orange. These results suggested that modification of the nuclear surface and of intranuclear constituents, leading to altered adhesiveness and dye binding, respectively, may reflect the activity of structurally latent hydrolases released in situ from lysosomal membranes labilized by exposure to hormone. The present results support the concept that lysosomal function may be involved in the coupling of initial steroid—receptor interaction at the cell membrane with hormone-dependent events in specific target cells.
HUMAN FOETAL ADRENAL 4-ENE-3-OXOSTEROID SYNTHESIS: AN INVESTIGATION OF [4-14C]PREGNENOLONE AND [4-14C]-DEHYDROEPIANDROSTERONE METABOLISM USING NEW TECHNIQUES
Authors: TAYLOR T. , HAMILTON W. 
Published: December 2008

SUMMARY
Human foetal adrenal slices were incubated with [4-14C]pregnenolone (20 foetuses) and [4-14C]dehydroepiandrosterone (18 foetuses). Product 4-ene-3-oxosteroids were isolated as a group and measured in toto by a double isotope dilution procedure. Production of compounds of the 4-ene-3-oxosteroid fraction was estimated over several time-intervals and relative to the protein content of the incubated tissue.
No conversion of [4-14C]pregnenolone by foetal adrenal tissue to 4-ene-3-oxosteroids was detectable although metabolism of the substrate to other compounds was indicated. Conversion of [4-14C]dehydroepiandrosterone to 4-ene-3-oxosteroids, principally androstenedione, occurred in incubations of tissue from 7 of the 10 male foetuses studied with this substrate, and from 2 of undetermined sex, but not from 6 female foetuses so studied. Testosterone formation from [4-14C]dehydroepiandrosterone was not detectable. There was no apparent variation in 4-ene-3-oxosteroid formation relative to foetal age in the range investigated (approximately 6–20 foetal weeks).
These results are interpreted, in the light of previous studies, as giving credence to the concept of substrate specificity in human foetal adrenal 4-ene-3-oxosteroid formation. The evidence that foetal adrenal androstenedione formation may be sex-dependent is considered, and the implications discussed.
THE EFFECT OF HYPOCALCAEMIA ON THE SECRETION OF CALCITONIN
Authors: WEST T. E. T. , O'RIORDAN J. L. H. , COPP D. H. , BATES R. F. L. , CARE A. D. 
Published: December 2008

SUMMARY
Hypocalcaemia was produced by i.v. infusion of EDTA into pigs from which the thyroid venous effluent could be quantitatively collected. Calcitonin in the effluent was measured by radioimmunoassay. Reduction of plasma calcium concentration rapidly suppressed the secretion of calcitonin. In contrast, as plasma calcium was raised slowly from hypocalcaemic levels by infusion of CaCl2, calcitonin secretion quickly returned and increased rapidly. The secretion rate observed when the plasma calcium concentration had been raised from hypocalcaemia to the initial normocalcaemic level was 3½–10 times greater than that observed during the normocalcaemia which pertained at the start of each experiment. A previous period of hypocalcaemia also produced an exaggerated response to a subsequent hypercalcaemic stimulus. It is suggested that the preconditioned response of calcitonin secretion increases the efficiency of the role of calcitonin in calcium homeostasis.
DISTRIBUTION OF ADRENOCORTICOTROPHIC HORMONE-STIMULATED ADENYLATE CYCLASE IN THE ADRENAL CORTEX
Authors: GOLDER MERIEL P. , BOYNS A. R. 
Published: December 2008

SUMMARY
The intra-adrenal distribution of adenylate cyclase was measured in microsections of guinea-pig and rat adrenals. Addition of α-adrenocorticotrophin-(1–24)-tetracosapeptide (α1–24ACTH) in vitro to sections of normal guinea-pig adrenals stimulated enzyme activity in glomerular—fascicular border zone tissue and reticular tissue. The intravenous injection of α1–24ACTH increased adenylate cyclase activity in sections of adrenal cortex from dexamethasone-treated guinea-pigs. Enzyme activity was enhanced in glomerular—fascicular border zone tissue, reticular and fascicular—reticular border zone tissue. In the rat, hypophysectomy reduced adrenal adenylate cyclase activity to undetectable levels within 48 h. Addition of α1–24ACTH to tissue sections in vitro augmented enzyme activity.
Adenylate cyclase activity was also measured in homogenates of whole guinea-pig adrenal tissue. α1–24ACTH (10, 100 and 1000 ng/ml) stimulated basal enzyme activity, whereas porcine insulin (400 pg/ml and 4 ng/ml) was without effect. Insulin inhibited the stimulation of adenylate cyclase activity by α1–24ACTH at concentrations of 10 ng/ml and 100 ng/ml. At higher concentrations of α1–24ACTH, insulin was without effect.
MORPHOLOGICAL RESPONSES TO CORTICOTROPHIN AND CYCLIC AMP BY ADULT RAT ADRENOCORTICAL CELLS IN MONOLAYER CULTURE
Authors: O'HARE M. J. , NEVILLE A. MUNRO 
Published: December 2008

SUMMARY
Confluent monolayer cultures of cells from the zona fasciculata and zona reticularis of the normal adult rat adrenal cortex were maintained with or without corticotrophin (ACTH) for up to 4 months, without proliferation of adrenal cells. Proliferating fibroblast-like cells, however, eventually overgrew the adrenal monolayer in cultures both with and without ACTH. Adrenocortical cells in culture, maintained without ACTH, spread rapidly to form a confluent monolayer, whereas cell spreading was markedly inhibited in the presence of ACTH. Exposure of previously unstimulated cells to ACTH or cyclic AMP caused the adrenal cells to retract with loss of confluence, the process being reversed when ACTH or cyclic AMP was withdrawn. Ultrastructural features of cells cultured with ACTH were typical of normal adrenocortical cells; in cultures without ACTH they were similar to those of adrenocortical cells found in the hypophysectomized rat.
THE SECRETION OF DEHYDROEPIANDROSTERONE AND DEHYDROEPIANDROSTERONE SULPHATE IN MAN
Authors: NIESCHLAG E. , LORIAUX D. L. , RUDER H. J. , ZUCKER I. R. , KIRSCHNER M. A. , LIPSETT M. B. 
Published: December 2008

SUMMARY
The secretion of dehydroepiandrosterone (DHA) and its sulphate (DHAS) was examined by measuring their concentrations in adrenal venous, gonadal venous, and peripheral venous plasma. Both steroids were secreted by the adrenal cortex and the rate of DHA secretion was higher than that of DHAS in seven out of eight subjects. Adrenocorticotrophin (ACTH) caused an increase in DHA and DHAS secretion by 15–30 min after administration. When ACTH was infused for 8 h, peripheral DHA concentrations increased at 2 h and decreased subsequently in five out of eight subjects suggesting depletion of substrate or cofactors for this biosynthetic pathway.
Gonadal secretion of DHA was present in each subject (eight women and two men) but DHAS secretion could not be demonstrated. Exogenous human chorionic gonadotrophin (HCG) caused an increase in plasma DHA. Examination of the diurnal variation of plasma DHA concentrations revealed a 40% decrease from 08.00 to 20.00 h.
EFFECT OF GONADOTROPHINS ON THE SECRETION OF OESTRADIOL-17β AND TESTOSTERONE BY THE RAT TESTIS
Authors: DE JONG F. H. , HEY A. H. , van der MOLEN H. J. 
Published: December 2008

SUMMARY
Concentrations of oestradiol-17β and testosterone were estimated in peripheral venous plasma and testicular venous plasma of adult male rats before and after administration of human chorionic gonadotrophin (HCG) or follicle-stimulating hormone (FSH). The concentration of oestradiol-17β in peripheral plasma, as measured with a radioimmunological technique, was 2·0 ± 0·9 (s.d.) pg/ml (n = 12). Peripheral testosterone concentrations were 2·4 ± 1·8 (s.d.) ng/ml (n = 21). Concentrations of oestradiol-17β and testosterone in testicular venous plasma were significantly higher than those in peripheral plasma. After intravenous administration of HCG (100 i.u.), oestradiol-17β and testosterone concentrations in testicular venous plasma increased significantly. After prolonged s.c. administration of HCG (5 days) the concentration of oestradiol-17β in testicular venous plasma did not change significantly, although the concentration of testosterone increased more than ten times. Intravenous administration of HCG after 5 days of pretreatment with HCG caused a significant increase in oestradiol-17β concentrations in testicular venous plasma. The increase in testosterone concentration was not significant under these conditions.
Intravenous administration of FSH did not change oestradiol-17β or testosterone concentrations in testicular venous plasma.
THE EFFECT OF PREGNANCY ON THE COLLAGEN OF THE UTERINE CERVIX OF THE MOUSE
Authors: RIMMER DIANE M. 
Published: December 2008

SUMMARY
The collagen content of the cervix of the pregnant mouse was found to be least on day 10 of pregnancy and greatest just before parturition (day 19). Similarly, the weight of cervical tissue was least on day 9 and greatest at parturition (day 20). However, the collagen concentration in the tissue was maximal on day 9 (7·54% of wet weight) and minimal on day 20 (1·56% of wet weight) because the collagen content decreased more than the weight during the first half of pregnancy and the weight increased more than the collagen during the latter part of pregnancy. Fluctuations in the trend of results were recorded early in the second half of pregnancy and steady changes were only observed in the last few days before parturition. On the first day post partum, conditions had returned to the oestrous state. The results are discussed with regard to the endocrine state of the animal and comparisons are made with changes in the rat cervix during pregnancy.
EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON TESTICULAR 5α-ANDROSTANE-3β-HYDROXYSTEROID DEHYDROGENASE, 3β-HYDROXYDEHYDROEPIANDROSTERONE DEHYDROGENASE AND ALCOHOL DEHYDROGENASE OF IMMATURE RATS
Authors: FROWEIN JOACHIM 
Published: December 2008

SUMMARY
Testicular enzymes related to steroid conversion were studied in infantile rats during sexual maturation, and the effect of human chorionic gonadotrophin (HCG) on the specific activities of the enzymes was analysed.
Activity of 5α-androstane-3β-hydroxysteroid dehydrogenase, which increases between days 20 and 30, was markedly enhanced after administration of HCG. Alcohol dehydrogenase activity, which is related to 3β-hydroxysteroid dehydrogenase activity, also increased after HCG treatment. The other enzyme activities investigated, i.e. 3β-hydroxyde-hydroepiandrosterone dehydrogenase and testosterone-17β-dehydrogenase, did not respond to HCG administration. These results suggest that different enzymes are responsible for the conversion of 3β-hydroxylated androgenic steroids and that the testicular alcohol dehydrogenase is not identical to the 3β-hydroxysteroid dehydrogenase described here.
On the assumption that HCG enhances enzyme activities indirectly by stimulating the synthesis of androgens which in turn produce the observed effect, different androgenic steroids (epiandrosterone, 5α-androstane-3,17-dione, 5α-dihydrotestosterone, 5α-androstane-3β,17β-diol) were tested for their ability to increase enzyme activities. None of these metabolites had an effect similar to that of HCG. The antiandrogen cyproterone (1,2α-methyl-6-chloro Δ4,6-pregnadien-17β-ol-3,20-dione) acetate, which was administered simultaneously with HCG, did not prevent the effect of HCG. From these results and other published reports it is concluded that in the testis of the infantile rat the metabolism of 5α-hydrogenated androgenic metabolites is stimulated by HCG.
THE MILK-EJECTION REFLEX OF THE RAT: A 20- TO 40-FOLD ACCELERATION IN THE FIRING OF PARAVENTRICULAR NEURONES DURING OXYTOCIN RELEASE
Authors: WAKERLEY J. B. , LINCOLN D. W. 
Published: December 2008

SUMMARY
Antidromically-identified paraventricular (PV) neurones were studied in the anaesthetized rat during milk ejection (ME) evoked by the natural stimulus provided by the suckling young. An intermittent pattern of ME was observed, though the ME interval was slightly longer (10–20 min) in the doe during unit recording than in unoperated or conscious animals (5–15 min). PV neurones displayed a steady background of spike discharge in both the non-lactating rat and lactating rat during suckling. The firing rates ranged from 0 to 9·4 spikes/s and were exponentially distributed with 32% of the units firing at <1 spike/s. Phasic patterns of discharge were seen in 18% of the units.
Fifty-eight per cent of the PV units displayed a stereotyped and explosive acceleration in spike activity some 15–20 s before the rise in intramammary pressure at ME. The peak firing rate during this brief (2–4 s) response was in the range of 24–84 spikes/s. A prominent after-inhibition was then displayed by these responsive units, though this second component of the response was variable in duration (7–56 s). The electrical activity of the remaining units, including all the cells with phasic discharge, was not correlated with ME.
There was no apparent change in the intensity of the suckling stimulus at the time of PV activation, i.e. 15–20 s before ME. Secondly, the activity of the PV neurones was not influenced by the rise in the intramammary pressure and the increased sucking of the pups at the time of ME. Simulation of an individual ME was obtained with both 1 mu. exogenous oxytocin, i.v., and electrical stimulation of the neurohypophysis (50 pulses/s for 4 s). The latencies to ME ranged from 7–14 s and 11–23 s, respectively.
In conclusion, an explosive increase in the electrical activity of PV neurones precipitates the release of oxytocin at ME.
PROLACTIN CONTENT OF CANINE PITUITARY GLAND
Authors: SALUJA P. G. , HAMILTON J. M. , GRONOW M. 
Published: December 2008

SUMMARY
The prolactin concentration in the dog pituitary gland was determined by isoelectric focusing of adenohypophysial extract in polyacrylamide gels followed by densitometry of the isolated stained hormone band. Dogs of both sexes and various ages (excluding newborn pups and weanlings) were studied. The bitches comprised animals at different stages of the oestrous cycle and also included a small number of pregnant, lactating or ovariectomized animals.
Low pituitary prolactin concentrations were found in males, sexually immature females and dioestrous females. Concentrations about 1·5 times as high occurred in oestrous, metoestrous (luteal) and ovariectomized females. Post-partum lactating bitches had the highest pituitary prolactin concentrations, these being double those occurring at dioestrus. With the exception of relatively high concentrations in ovariectomized bitches, these results are in good agreement with findings in the rat, mouse and rabbit. The persistence of high pituitary prolactin levels throughout metoestrus was believed to be associated with differences between the canine and murine reproductive cycle. Age did not influence pituitary prolactin levels in either males or females.
ULTRASTRUCTURAL PRESERVATION OF THE DENSE CORE OF POSTERIOR PITUITARY NEUROSECRETORY GRANULES AND ITS IMPLICATIONS FOR HORMONE RELEASE
Authors: MORRIS J. F. , CANNATA M. A. 
Published: December 2008

SUMMARY
Neural lobe neurosecretory granules (NSG) have been studied after different fixation procedures. When the pH of prefixation in a triple-aldehyde solution was varied, the dense core of NSG's was best preserved at pH's 5·0 and 6·0 but at pH's 7·0 and 8·0 loss of density of the granule core occurred and was most marked at pH 8·0. Increased duration of prefixation resulted in progressive loss of density of the granule core at pH's 7·0, 7·3 and 8·0, but at pH's 5·0 and 6·0 granules remained dense-cored, even after 24 h prefixation. When osmium tetroxide was used alone as a fixative, dense cores were again best preserved at acidic pH. This finding was correlated with studies in vitro in which the fixative solutions were reacted with aqueous suspensions of known components of the NSG's.
The neural lobes of animals stimulated to release hormone by substitution of 2% NaCl solution for drinking water were also studied after fixation at different pH's. There was a significant decrease in the number of NSG's after treatment but no significant decrease in the proportion of NSG's which retained the dense-cored appearance at any pH. This suggests that hormone loss from the neural lobe is associated with loss of entire granules rather than with a reduction of density of the granule core and this finding is discussed in the light of theories on the mechanism of hormone release.
EFFECTS OF ADRENALECTOMY AND/OR DEFICIENCY OF PITUITARY PROLACTIN SECRETION ON INITIATION AND MAINTENANCE OF LACTATION IN MICE
Authors: NAGASAWA HIROSHI , YANAI REIKO 
Published: December 2008

SUMMARY
In order to examine the effects of deficiency of adrenal corticosteroids and/or prolactin on the initiation and maintenance of lactation in mice, C3H/He female mice were adrenalectomized and/or implanted during days 13–15 of pregnancy with a pellet of 2-bromo-α-ergocryptine (EC), a potent inhibitor of pituitary prolactin secretion. Average body weights of the young and mammary contents of DNA and RNA were determined on days 0 (day of parturition) and 10 of lactation. On day 0, no differences in these parameters were found among groups, and plenty of milk was present in the stomachs of the young. Furthermore, the treatments did not affect the duration of pregnancy, the number of still-born young or the maternal behaviour at parturition. All young in the group adrenalectomized and implanted with EC died by day 2. Adrenalectomy or implantation of EC retarded the growth of young after day 2 and decreased markedly the mammary nucleic acid content on day 10. These results strongly suggest that adrenal corticosteroids and prolactin play minor roles in the initiation of lactation at parturition, while they are indispensable for the maintenance of lactation in mice.
ADRENOCORTICAL FUNCTION IN THE AUSTRALIAN BRUSH-TAILED POSSUM TRICHOSURUS VULPECULA (KERR)
Authors: THAN KHIN AYE , McDONALD I. R. 
Published: December 2008

SUMMARY
The peripheral plasma concentration and secretion rate of cortisol in the conscious marsupial brush-tailed possum Trichosurus vulpecula (Kerr) was investigated under basal conditions and during maximal corticotrophin (ACTH) stimulation.
Cortisol concentration in peripheral plasma was 0·92 ± 0·48 (s.d.) μg/100 ml in males, and 1·01 ± 0·57 in females. It was lowest at 08.00 h, when the possums were asleep and not easily aroused. Although there was a high variance, a third degree polynomial fitted the data plotted against time over 24 h at the 95% level of confidence, indicating a diurnal periodicity.
Ether anaesthesia, porcine and synthetic (24 amino acids) ACTH caused plasma cortisol concentrations to rise to maxima of no more than 7 μg/100 ml. The dose-response curve to ACTH indicated a maximum response at 0·12 i.u./kg/h with a potency of approximately 1/6 that found in sheep and 1/20 that found in man.
Cortisol secretion rates in non-stimulated possums were 2·71 ± 1·01 μg/kg/h in males and 4·32 ± 1·74 in females. They increased during maximal ACTH stimulation to 6·24 ± 1·58 μg/kg/h in males, and 13·28 ± 7·82 in females. Metabolic clearance rates were lowest in animals not accustomed to repeated blood sampling and rose in subsequent experiments.
It is concluded that the adrenal cortex of Trichosurus, like that of eutherian mammals, responds to changes in activity, stressful stimuli and ACTH, but quantitatively, the responses to these stimuli are very much lower.
FACTORS INFLUENCING THE SECRETION OF LUTEINIZING HORMONE AND OVULATION IN RESPONSE TO ELECTROCHEMICAL STIMULATION OF THE PREOPTIC AREA IN RATS
Authors: VELASCO M. E. , ROTHCHILD I. 
Published: December 2008

SUMMARY
Factors affecting luteinizing hormone (LH) secretion in response to stimulation of the preoptic area (POA) of the forebrain in rats were explored by determining serum LH levels after electrochemical stimulation of the POA. In rats made anovulatory by exposure to constant light (CLA rats), peak concentrations of LH in serum were found 2 h after stimulation with 5–15 mC, and 1 h after stimulation with 0·5–1 mC. The peak levels increased with increasing doses between 0·5 and 15 mC. The incidence of rats ovulating and the mean number of ovulations/rat were roughly proportional to the stimulating dose, but a plateau was reached between 5 and 10 mC. A threshold level of serum LH seemed to be necessary for ovulation, and the incidence of ovulations of six ova or more/rat increased with the increase in peak serum LH level.
Preoptic-roof section, which cuts dorsal afferents to the POA, enhanced the increase in serum LH in response to POA stimulation in CLA rats, while sodium pentobarbitone anaesthesia decreased the response. In both cases, the incidence of ovulation and the number of ovulations/rat were not different from values found in POA-stimulated control CLA rats showing the same peak serum LH level.
In normal cyclic rats the response of serum LH to stimulation was much greater on the morning of pro-oestrus than on that of oestrus; at prooestrus a second rise occurred between 17.00 and 19.00 h. Three days after ovariectomy the basal level of LH increased; these ovariectomized rats showed a small increase in response to a dose of 5 mC. Treatment with 20 μg oestradiol benzoate at the time of ovariectomy, however, resulted in a lowered basal LH level, but the peak response to 5 mC was almost as great as that found in similarly stimulated intact CLA rats. In intact males and in neonatally androgen-treated females the peak levels of serum LH in response to doses of 5 or 15 mC were equivalent to those in CLA females in response to doses of only 1–5 mC.