bluuebunny/crossref_metadata_2025_split huggingface dataset:
OBSERVATIONS ON THE LOCALIZATION OF RECENTLY SYNTHESIZED CATECHOLAMINES IN CHROMAFFIN CELLS AFTER THE INJECTION OF l-[2,5,6-3H]DOPA
Authors: COUPLAND R. E. , KOBAYASHI S. , KENT CHRISTINE 
Published: December 2008

SUMMARY
The fate of l-[2,5,6-3H]DOPA, and the intracellular localization of its metabolic products dopamine, noradrenaline and adrenaline, have been determined by the simultaneous use of assay techniques following separation of amines by chromatography and light and electron microscopic autoradiography.
During the first 24 h after i.v. or i.p. injection of [3H]DOPA, synthesis of the above catecholamines occurred. Throughout this time the labelled amines were associated with chromaffin granules or immediately adjacent cytosol and not with either the Golgi complex or rough endoplasmic reticulum. Labelling of chromaffin granules occurred simultaneously throughout the cell and there was no evidence of regions containing recently labelled granules and others containing previously charged (older) granules. Adrenaline-storing cells took up [3H]DOPA and its products more rapidly and lost recently synthesized adrenaline more rapidly than noradrenaline-storing cells took up and stored their equivalent amines. This was in keeping with a more rapid turnover of catecholamines in adrenaline-storing elements.
COMPARISON OF THE REDOX BIOASSAY WITH OTHER ASSAYS FOR LUTEINIZING HORMONE
Authors: KRAMER ROSANNE M. , HOLDAWAY I. M. , CRIGHTON D. B. , McNEILLY A. S. , REES LESLEY H. , CHARD T. 
Published: December 2008

SUMMARY
The cytochemical (redox) bioassay for LH has been compared with established LH assays. Measurements made by redox bioassays were considerably lower than those made by radioimmunoassay in human female plasma samples obtained at mid-cycle. There was no apparent relationship between measurements on incubation media from cultures of sheep pituitary glands made by redox bioassay and the ovarian ascorbic acid depletion (OAAD) assay. After polyacrylamide gel electrophoresis of a crude extract of a human pituitary gland, redox LH measurements were lower than those of the OAAD assay and radioimmunoassay in the cathodal segments of the gel. By contrast, there was reasonable agreement between LH measurements made by radioimmunoassay and redox assay in cathodal fractions from gel electrophoresis of a purified pituitary LH preparation. Follicle-stimulating hormone, and the α- and β-subunits of LH depressed the response of intact LH in the redox assay; this might explain the relatively low levels of LH measured by redox assay in some of the experiments described. Which type of assay best reflects the biological activity of LH in man remains to be determined.
BLOOD CORTICOSTEROIDS IN AUSTRALIAN MARSUPIAL AND PLACENTAL MAMMALS AND ONE MONOTREME
Authors: ODDIE C. J. , BLAINE E. H. , BRADSHAW S. D. , COGHLAN J. P. , DENTON D. A. , NELSON J. F. , SCOGGINS B. A. 
Published: December 2008

SUMMARY
Peripheral blood corticosteroid levels were determined in nine species of Australian marsupial (Eastern grey kangaroo, black-tailed, Bennett's and pademelon wallabies, quokka, wombat, koala and Western native and tiger cats), one species of monotreme (echidna) and one placental Australian mammal (dingo). Animals were obtained or bled with minimal disturbance and came from areas considered to have adequate sodium content of the vegetation. Aldosterone, corticosterone, cortisol, 11-deoxycorticosterone and 11-deoxycortisol were measured and levels found to be similar to five introduced eutherian species (sheep, cow, dog, fox and man) with the exception of the koala and the wombat. Cortisol was the predominant corticosteroid, except in the koala, which produced corticosterone in relatively the greatest quantity, and the wombat which produced more 11-deoxycortisol. Steroid levels were generally low in the wombat. ACTH administered to the koala changed its pattern of corticosteroid secretion from predominantly corticosterone to cortisol. In the dingo, administration of ACTH caused rises in corticosteroid levels similar to those seen in most other eutherian mammals.
DISTRIBUTION OF PROSTAGLANDINS E2 AND F2α WITHIN THE FOETOPLACENTAL UNIT THROUGHOUT HUMAN PREGNANCY
Authors: WILLMAN EVE A. , COLLINS W. P. 
Published: December 2008

SUMMARY
The concentrations of prostaglandin E2 and F2α have been measured by radioimmunoassay in portions of cord, placenta, amnion, chorion, decidua and myometrium. The samples were obtained at defined periods of pregnancy, and the results have been compared with those obtained from the analyses of endometrial and myometrial tissue removed from women during the secretory phase of a menstrual cycle.
The results showed that during pregnancy the mean concentration of prostaglandin E2 was higher (27–518%) than the corresponding value for prostaglandin F2α in all tissues. At term the concentration of prostaglandin E2 (ng/100 mg wet weight of tissue, mean ± S.D.) was higher in the umbilical cord 5·54 ± 0·88), decidua (4·02 ± 1·78) and myometrium (4·19 ± 1·06), than in the amnion (2·25 ± 1·27), chorion (1·64 ± 0·63) or placenta (1·04 ± 0·25). During labour there was a significant rise (P < 0·0005, Student's `t' test) in the concentration in decidua (10·76 ± 4·45), and to a lesser extent (P < 0·05) in the myometrium (5·84 ± 2·65) and amnion (4·77 ± 2·51). The overall concentration in decidua during the first trimester (3·09± 1·02) was significantly lower (P < 0·005) than in endometrial tissue (16·82 ± 10·13). The concentration was lower in myometrial tissue from non-pregnant subjects (2·90 ± 2·21), than in the corresponding tissue removed at term (4·19 ± 1·06) or during labour (5·84 ± 2·65).
The results for prostaglandin F2α showed a similar pattern, but the values were significantly lower in the umbilical cord, and the percentage changes in concentration in the decidua and myometrium were of a higher magnitude.
BILATERAL ADRENALECTOMY OF LAMBS IN UTERO: EFFECTS ON MATERNAL HORMONE LEVELS AT INDUCED PARTURITION
Authors: FLINT A. P. F. , ANDERSON ANNE B. M. , GOODSON JANE D. , STEELE PENELOPE A. , TURNBULL A. C. 
Published: December 2008

SUMMARY
Progesterone, 17α,20α-dihydroxypregn-4-en-3-one, androstenedione, total unconjugated oestrogen and oestrone sulphate have been measured by radioimmunoassays in maternal utero-ovarian venous, maternal peripheral venous and/or foetal posterior vena caval plasma from six sheep bearing bilaterally adrenalectomized lambs, in which premature parturition was induced by administration of glucocorticoid. Three of the ewes were ovariectomized, and in one of these three animals the foetal testes were also excised, at the time of foetal adrenalectomy. Adrenalectomy was judged to be complete on the basis of plasma cortisol levels in the neonatal lambs, and by examination of the site of ablation at necropsy. In all cases foetal administration of glucocorticoid led to the onset of labour, and lambing, and in all animals the hormonal changes preceding parturition were indistinguishable (either qualitatively or quantitatively) from the changes observed in animals carrying intact lambs. Since therapy with glucocorticoid alone successfully compensates for ablation of the foetal adrenal cortex, it is suggested that glucocorticoid is the only adrenal product required to cause parturition, and that foetal adrenal secretion of androgens may be unnecessary.
EFFECTS OF EXOGENOUS DEHYDROEPIANDROSTERONE SULPHATE ON VARIOUS ENZYMES AND ON STEROID METABOLISM IN THE GUINEA-PIG
Authors: BERGHEIM ECKART , OERTEL G. W. 
Published: December 2008

SUMMARY
Treatment of male guinea-pigs daily with an oral dose of 2 mg dehydroepiandrosterone (DHA) sulphate/100 g body weight for 2 weeks significantly reduced the glucose-6-phosphate dehydrogenase (G-6-PDH) activity of erythrocytes, liver, kidney and testis. Lactate dehydrogenase activity in plasma also decreased, but l-aspartate: 2-oxoglutarate aminotransferase (GOT) and l-alanine: 2-oxoglutarate aminotransferase (GPT) activity in plasma remained unaffected. In liver and kidney, however, a significant rise in GOT and GPT was observed.
A 2- to 3·7-fold increase of C19-steroids was observed in plasma, liver and kidney. In extracts of liver and kidney more than 60% of steroids were isolated from the sulphatide fraction. Only minor changes were detected in the metabolic pattern of C19-steroids, 17-hydroxysteroids prevailing in the free and sulphatide fractions, while 17-oxosteroids predominated in the sulphate and glucuronide fractions.
A slight rise of cyclic AMP concentrations in liver and kidney tissue was attributed to the inhibition of phosphodiesterase by the DHA/G-6-PDH system.
REGULATION BY TESTOSTERONE AND SERUM PROTEIN OF DNA SYNTHESIS IN THE DEVELOPING EPIDIDYMIS OF THE RAT
Authors: MAJUMDER G. C. , TURKINGTON R. W. 
Published: December 2008

SUMMARY
Rates of DNA synthesis were measured as an index of cellular proliferation during the pubertal development of the rat epididymis. A highly reproducible pattern of DNA synthesis was defined by (1) a prepubertal, testosterone-insensitive peak of DNA synthesis at 25 days; (2) a dramatic decrease in DNA synthesis with the onset of puberty; (3) a major burst of testosterone-dependent synthesis peaking at 40 days in the head of the epididymis and at 40–60 days in the tail; (4) a fall to low levels as the adult organ weight was attained. An organ culture system was defined and utilized to analyse further the hormonal dependence of DNA synthesis in the epididymis. Testosterone and dihydrotestosterone failed to activate DNA synthesis at any stage of development in vitro. DNA synthesis was stimulated 100–300% by insulin at supra-physiological concentrations and by protein serum factor(s) at physiological concentrations. The serum activity was stable to heat treatment at 60 °C, destroyed by heating at 70 °C, and was present in the sera of hypophysectomized animals. These results indicate a primarily 'permissive' role for the action of testosterone on DNA synthesis in the epididymis: testosterone acts to permit the expression of a developmental 'programme' of cell proliferation which is activated by specific protein(s) in serum.
EFFECT OF ALDOSTERONE ON LITHIUM PERMEABILITY OF RAT COLON MUCOSA
Authors: DOLMAN DIANA , EDMONDS C. J. , SALAS-COLL C. 
Published: December 2008

SUMMARY
The effect of aldosterone on the ionic composition of colonic epithelial cells and on lithium absorption rate was studied by experiments on rats in vivo. Aldosterone considerably increased the rate of sodium absorption without measurably altering the sodium and potassium content of the epithelium. Aldosterone did not alter the electrical resistance of the tissue. With lithium in the lumen, the net sodium fluxes in the colon were similar in normal and aldosterone-stimulated rats but the rate of diffusion of lithium across the epithelium was greater in the aldosterone-stimulated group. The amount of lithium accumulating in the epithelial layer was also considerably increased by aldosterone stimulation. Aldosterone appears to increase the permeability of the mucosal (luminal) barrier allowing increased entry of lithium into the colonic epithelial cells.
EFFECT OF CYPROTERONE ACETATE ON ANDROGEN-DEPENDENT SYNTHESIS OF α2u GLOBULIN IN RATS
Authors: ROY A. K. 
Published: December 2008

SUMMARY
Cyproterone acetate (CA, 2·5 mg/100 g body wt) inhibited androgenic induction of α2u globulin in spayed rats. In mature male rats, which normally produce α2u globulin, ten daily injections of CA did not inhibit synthesis of this protein. Long-term treatment of mature male rats (two injections every week for 12 weeks) showed only slight inhibition of α2u synthesis after 10 weeks of CA treatment. CA also failed to compete with 5α-dihydrotestosterone for the cytosol androgen-binding protein of male rat liver. The inhibitory effect of CA on the primary induction of α2u globulin in the spayed rat and its lack of effect on continued synthesis of this protein in maximally induced mature male rats are consistent with the hypothesis of a two-step mechanism for androgenic regulation of α2u synthesis, an initial CA-sensitive step followed later by a CA-insensitive step.
SUSTAINED EFFECTS OF SYNTHETIC OVARIAN STEROIDS ON RAT MYOMETRIAL CONTRACTILITY
Authors: PARKINGTON HELENA C. , LIPTON A. 
Published: December 2008

SUMMARY
Ovariectomized rats were given a single dose of synthetic oestrogen or progestogen, or both combined.
On selected days after treatment one rat from each treatment group was killed and myometrial contractility in response to spasmogens was measured isometrically in isolated tissue baths. Contractility persisted at a low level after ovariectomy without steroid replacement (controls) for the 60 days of the experiment.
The powerful potentiating action of oestrogen reached a maximum in about 10 days and sustained a high level thereafter.
Progestogen treatment did not influence contractility to a significant degree when compared with saline, except that the contractions were sometimes of higher frequency and more irregular in size.
There was a less powerful potentiating action on contractility with combined oestrogen and progestogen treatment than with oestrogen alone. It reached a maximum in 4 days and declined more rapidly than with the oestrogen-treated preparation but was still vigorous for up to 30 days.
CHANGES IN THE SECRETION OF OVARIAN STEROIDS AND PITUITARY LUTEINIZING HORMONE IN THE PERI-OVULATORY PERIOD IN THE EWE: THE EFFECT OF PROGESTERONE
Authors: BAIRD D. T. , SCARAMUZZI R. J. 
Published: December 2008

SUMMARY
The secretion rates of oestradiol, androstenedione and progesterone and the peripheral plasma concentration of LH were measured in 12 ewes with ovarian autotransplants before and after luteal regression induced by a single intramuscular injection of a synthetic prostaglandin (PG) analogue, 16-aryloxyprostaglandin F2α (I.C.I. 80996). Luteal regression was followed by a fourfold rise in the basal concentration of LH and increased secretion of oestradiol. In five out of six ewes there was a discharge of LH with the peak occurring 36–78 h after the injection of the PG analogue. The secretion of oestradiol declined from 3·68± 1·08 to 0·33± 0·6 (s.e.m.) ng/min in the 24 h following the LH peak (P < 0·001). In the remaining six ewes in which progesterone was implanted subcutaneously 24 h after the injection of PG analogue, follicular development was suppressed as indicated by the low secretion of oestradiol and androstenedione. The basal concentration of LH fell to values similar to those observed during the luteal phase after the implant of progesterone. The secretion of androstenedione followed a similar pattern to that of oestradiol in those ewes which showed presumptive evidence of ovulation. These results suggest that progesterone reinforces the negative feedback effects of oestrogen in the ewe.
BRANCHIAL SODIUM EXCHANGE IN SEAWATER-ADAPTED TILAPIA MOSSAMBICA: EFFECTS OF PROLACTIN AND HYPOPHYSECTOMY
Authors: DHARMAMBA M. , MAETZ J. 
Published: December 2008

SUMMARY
The effects of exogenous prolactin and hypophysectomy were tested on Na exchange across the gills of Tilapia mossambica adapted to sea-water.
Exogenous prolactin produced a 75% decrease of both total Na influx and Na efflux. Total Na influx was measured simultaneously with the drinking rate. Water ingestion stopped almost completely in prolactin-treated fish. Thus branchial net excretion flux of Na was reduced 75% by prolactin.
Hypophysectomy produced a 50% inhibition of Na efflux across the gill.
COMPARISON BETWEEN THE BINDING OF 19-NORTESTOSTERONE, 5α-DIHYDROTESTOSTERONE AND TESTOSTERONE IN RAT PROSTATE AND BULBOCAVERNOSUS/LEVATOR ANI MUSCLE
Authors: KRIEG M. , DENNIS M. , VOIGT K. D. 
Published: December 2008

SUMMARY
Specific binding of [3H]19-nortestosterone in the 100000 g cytosol of the rat bulbocavernosus/levator ani muscle (BCLA) and prostate was demonstrated by agargel electrophoresis at low temperature and compared qualitatively and quantitatively with the binding of tritiated testosterone and 5α-dihydrotestosterone (5α-DHT). Both tissues showed a greater binding affinity for 5α-DHT than for 19-nortestosterone, with testosterone binding the least well of the three. The relative binding affinities in the BCLA and prostate were: 19-nortestosterone: testosterone = 1·4, 19-nortestosterone: 5α-DHT = 0·7. The differences were statistically significant (P < 0·02). The concentrations of receptor sites for 5α-DHT were 171 ± 20 (s.d.) fmol/mg prostatic cytosol protein and 24 ± 4 (s.d.) fmol/mg BCLA cytosol protein. The in-vitro metabolism of the three steroids in both tissues was also investigated by thin-layer chromatography. After incubating for 2 h at 0 °C the prostate was shown to reduce 26% of the 5α-DHT to androstanediols whilst the BCLA showed a 5% conversion. Testosterone was converted by the prostate to 5α-DHT (10%) and the androstanediols (6%) whilst the BCLA showed little activity in this respect. Comparing these in-vitro data with in-vivo findings from the literature, in both organs there is a positive correlation of the extent of binding in vitro to the stimulation of growth in vivo, bearing in mind that testosterone is metabolized to 5α-DHT in the prostate whilst in the BCLA, 5α-reductase is essentially absent.
ENDOCRINE EFFECTS OF MASTURBATION IN MEN
Authors: PURVIS K. , LANDGREN B.-M. , CEKAN Z. , DICZFALUSY E. 
Published: December 2008

SUMMARY
The levels of pregnenolone, dehydroepiandrosterone (DHA), androstenedione, testosterone, dihydrotestosterone (DHT), oestrone, oestradiol, cortisol and luteinizing hormone (LH) were measured in the peripheral plasma of a group of young, apparently healthy males before and after masturbation. The same steroids were also determined in a control study, in which the psychological anticipation of masturbation was encouraged, but the physical act was not carried out. The plasma levels of all steroids were significantly increased after masturbation, whereas steroid levels remained unchanged in the control study. The most marked changes after masturbation were observed in pregnenolone and DHA levels. No alterations were observed in the plasma levels of LH.
Both before and after masturbation plasma levels of testosterone were significantly correlated to those of DHT and oestradiol, but not to those of the other steroids studied. On the other hand, cortisol levels were significantly correlated to those of pregnenolone, DHA, androstenedione and oestrone.
In the same subjects, the levels of pregnenolone, DHA, androstenedione, testosterone and DHT in seminal plasma were also estimated; they were all significantly correlated to the levels of the corresponding steroid in the systemic blood withdrawn both before and after masturbation.
As a practical consequence, the results indicate that whenever both blood and semen are analysed, blood sampling must precede semen collection.
STIMULATION OF INTRA-UTERINE GROWTH IN RAT BY α-MELANOCYTE-STIMULATING HORMONE
Authors: SWAAB D. F. , VISSER M. , TILDERS F. J. H. 
Published: December 2008

SUMMARY
We have studied whether endogenous α-MSH has a function in stimulating intra-uterine growth in the rat. The approach used was to determine whether or not this hormone is present during the intra-uterine growth spurt, and if binding of endogenous foetal α-MSH by antibodies would inhibit this growth.
Antibodies against α-MSH or ACTH 1-24, either purified or non-purified, induced immunofluorescence in the intermediate lobe of adult male control rats. Using purified anti-α-MSH, fluorescence appeared in the foetal intermediate lobe on day 18 of pregnancy, the day that biologically active MSH was first seen. A negative correlation was observed between the pituitary MSH content and foetal body weight only on day 19 of pregnancy. Injection of purified anti-α-MSH induced a drop in foetal body weight, but no effect on placental weight was observed. Purified anti-ACTH 1-24 had no effect upon body weight but caused an increase in placental weight.
These results support our previous findings and indicate that endogenous MSH has a function in the stimulation of foetal growth.
BINDING OF HUMAN GROWTH HORMONE TO HEPATIC LACTOGENIC BINDING SITES: REGULATION BY OESTROGENS AND ANDROGENS
Authors: HERINGTON A. C. , BURGER H. G. , VEITH NOELLE M. 
Published: December 2008

SUMMARY
The binding of 125I-labelled human growth hormone (HGH) to the 'lactogenic' binding sites of rat liver membranes has been shown to be highly dependent on the oestrogen and androgen status of the animal from which the membranes were prepared. Oestradiol treatment of either male or female rats induced a highly significant rise in HGH binding. The minimum effective dose used was 2–5 μg/day and the rise in HGH binding was apparent after 4 days of treatment. Following cessation of oestradiol treatment of male rats HGH binding declined with a half-time of approximately 9 days. In contrast to the stimulatory effect of oestrogen, treatment of female rats with testosterone propionate (minimum effective dose 100–200 μg/day) led to a marked reduction in HGH binding. The influence of both oestrogens and androgens was confirmed following the removal of endogenous sex steroids by adrenalectomy–ovariectomy of female rats and castration of male rats. Scatchard analysis showed that, with the possible exception of adrenalectomy–ovariectomy, all pharmacologically and physiologically induced changes in HGH specific binding reflected changes in binding site capacity; there were no changes in binding affinity. While earlier studies have indicated that the oestrogen effect is primarily indirect and is mediated by the pituitary gland, the mode of action of the androgens is currently unknown. The relatively slow response of HGH binding to hormonal changes would support an indirect action for both the sex steroids. The stimulatory effect of oestrogens and the inhibitory effect of androgens may provide an explanation for the marked sex difference in HGH binding to rat liver membranes.
THE INTERRELATIONSHIP BETWEEN PROGESTERONE AND LUTEINIZING HORMONE DURING THE OVULATION CYCLE OF THE HEN (GALLUS DOMESTICUS)
Authors: ETCHES R. J. , CUNNINGHAM F. J. 
Published: December 2008

SUMMARY
The existence of a circadian rhythm in the sensitivity of the hypothalamus of the laying hen to stimulation by progesterone was investigated by injecting 0·5 mg progesterone subcutaneously during the proposed period of maximum insensitivity. Following this treatment increases in plasma concentrations of both LH and progesterone were observed which were comparable to the spontaneous preovulatory rises in the plasma levels of the hormones.
The ability of either progesterone or luteinizing hormone releasing hormone (LH-RH) to induce premature ovulation varied according to the stage of follicular development. Neither hormone was more than 28% effective when injected within 6·5 h of the previous ovulation, whereas both hormones were 100% effective approximately 27 h after the terminal ovulation of a clutch sequence. Failure to ovulate in response to LH-RH given 6·5 h after ovulation was associated with a lack of progesterone secretion.
Both LH and progesterone were secreted when ovulation was induced by injections of either LH-RH or progesterone, and LH was secreted in response to progesterone given 6·5 h after ovulation. These results demonstrate that progesterone stimulates the secretion of LH and LH stimulates the secretion of progesterone. The precise physiological role of these two hormones, however, was not established.