bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE INFLUENCE OF SERUM ON UPTAKE, CONVERSION AND ACTION OF TESTOSTERONE IN RAT PROSTATE GLANDS IN ORGAN CULTURE
Authors: LASNITZKI ILSE , FRANKLIN HILARY R. 
Published: December 2008

SUMMARY
Explants of ventral rat prostates were incubated with [1,2-3H]testosterone in media (1) without serum, (2) with horse or calf serum, and (3) with human male or human pregnancy serum. With all sera the uptake of testosterone fell with rising serum content. At the same concentration, the uptake of testosterone and the amounts of dihydrotestosterone and androstanediol formed were significantly lower in explants incubated with pregnancy serum than in those incubated with male serum. Since testosterone binding is markedly higher in pregnancy than in male serum it was concluded that only the free unbound form of the hormone may be available to the target tissue. This was supported by findings that the degree of maintenance by testosterone in prostatic explants grown for 6 days without serum, or in the presence of either male or pregnancy serum, was closely related to the uptake and metabolism of testosterone under these three conditions.
The results suggest that the degree of testosterone binding regulates the supply of hormone to the target organ and, thus, influences its biological action.
STUDIES ON THE MECHANISM OF ACTION OF ANGIOTENSIN ON FLUID TRANSPORT BY THE MUCOSA OF RAT DISTAL COLON
Authors: DAVIES N. T. , MUNDAY K. A. , PARSONS B. J. 
Published: December 2008

SUMMARY
A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa.
Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.
GLUCAGON RELEASE FROM THE PANCREAS OF THE NEWBORN RAT
Authors: EDWARDS J. C. , ASPLUND K. , LUNDQVIST G. 
Published: December 2008

SUMMARY
A solid phase radioimmunoassay for glucagon was specially modified in order to overcome the problems involved in the measurement of glucagon release from incubated pieces of pancreas. The modified immunoassay procedure was used to study glucagon release from pieces of pancreas taken from newborn rats aged from 1 to 20 days. The glucagon content of rat pancreas was also measured during this period.
It was found that glucagon release from rat pancreas was stimulated by arginine and inhibited by octanoic acid at 1 and 2 days of age. However, glucagon release at 3 days of age was low, and between 3 and 7 days of age glucagon release could not be inhibited by octanoic acid or stimulated by arginine. At 10 and 20 days of age, the stimulatory action of arginine and the inhibitory action of octanoic acid were again noted. Glucagon release, measured at several ages, was not significantly affected by changes in glucose concentration. The glucagon content of the rat pancreas rose to a maximum at 5 days of age and then decreased gradually over a period of 90 days.
It is suggested that the low rate of glucagon release between 3 and 7 days of age may be a result of the high levels of blood fatty acids and ketone bodies found in the rat during this period.
THE OLFACTORY RESPONSE OF MICE TO URINE AND EFFECTS OF GONADECTOMY
Authors: DAVIES V. JANE , BELLAMY D. 
Published: December 2008

SUMMARY
Using a standard arena technique, the reactions of groups of albino mice were noted in response to traps baited with urine. The response was measured in terms of latency, duration of investigatory visit, total investigation time and number of visits.
Because of a high level of variability between individuals, many of the results were not significant, but it was demonstrated that urine contained olfactory attractants and there was a suggestion that it might also contain repellents. Animals showed a positive response to traps baited with urine from the opposite sex and where there was a difference in response to urine produced during the night and urine produced during the day, 'night' urine generally elicited a stronger response than 'day' urine. Males reacted negatively to male urine, whereas females were more strongly attracted to female urine than to male urine. The attractiveness of female urine to male mice, as measured by duration of investigatory visit, was increased twofold during pregnancy and threefold during oestrus. Oestrous urine tended to be more effective than dioestrous urine. Female urine stored at −10 °C was more attractive to male mice than fresh female urine. After prepubertal castration, males showed no preference for oestrous urine over dioestrous urine. Both normal and prepubertally castrated males, however, spent less time sniffing urine from spayed females than urine from females in oestrus or from non-oestrous females. There was evidence that intact male mice spent more time investigating female urine odours than did castrated mice, but this did not apply to dioestrous urine.
ADRENAL AND TESTICULAR CONTRIBUTION TO PLASMA OESTROGENS
Authors: SAEZ JOSÉ M. , MORERA ANNE M. , DAZORD ALICE , BERTRAND JEAN 
Published: December 2008

SUMMARY
The concentration of oestrone (E1) and oestradiol (E2) in plasma was measured by a radioimmunological method. In five premenopausal women, ovariectomy provoked a significant fall in the concentrations of E1 and E2. In 11 subjects of both sexes with cancer, dexamethasone (20 μg/kg/day) caused a significant fall in the levels of cortisol (84 ± 9·5%) and E1 (55 ± 16%), but not in E2 (2 ± 18%). Ninety minutes after administration of tetracosactrin, the increase in concentration of cortisol (80 ± 30%) and of E1 (70 ± 49%) was highly significant: that of E2 (5 ± 12%) was not. Similar results were observed in four subjects during infusion of corticotrophin. In six subjects, plasma concentration of E1, androstenedione and dehydroepiandrosterone was higher in the adrenal vein than in a peripheral vein, but the concentration of E2 and of testosterone was similar in the two samples. In two men, the concentration of androgens and oestrogens was measured in plasma from a peripheral vein and in plasma of mixed origin from the renal and the spermatic vein. The level of E2 was higher in plasma from the renal—spermatic mixture than in that from the peripheral vein, but the concentration of E1 was similar. All these results suggest that: (1) the adrenal secretes only 17-oxo androgens and oestrogens whereas in the testicular secretion, 17β-hydroxylated compounds predominate; (2) in men, nearly all of the E2 is secreted directly or indirectly by the testes, but the main source of E1 is the adrenal; (3) in postmenopausal women, most of the E1 also derives from the adrenal gland.
THE ZONA GLOMERULOSA AND CORTICOTROPHIN: A GENETIC STUDY IN MICE
Authors: SHIRE J. G. M. , STEWART J. 
Published: December 2008

SUMMARY
CBA/FaCam mice have adrenals with a well-developed zona glomerulosa. This zone is poorly developed in mice of the Peru strain, although the production of aldosterone is similar in the two strains. The zona glomerulosa was considerably reduced in CBA mice treated with synthetic corticotrophin (ACTH). In these mice degeneration of the adrenal X zone took the form typical of Peru mice. Treating Peru mice with dexamethasone resulted in the appearance of a wide zona glomerulosa, presumably as a consequence of lowered levels of ACTH in plasma. The hypothesis of relatively high levels of ACTH in Peru mice also received support from the relatively small spleens and large adrenals found in mice of this genotype. A significant negative correlation existed between the width of the zona glomerulosa and the weight of cortical tissue for the two strains and their F1 hybrid. This correlation did not, however, hold for mice of the genetically heterogeneous backcross generations. Thus the variation in the histological appearance of the subcapsular tissue was not causally related to differences in the mass of steroidogenic tissue.
The relationships between the visibly differentiated zona glomerulosa, the cells that produce aldosterone, and their control systems are discussed in the light of theories about the relationship between structure and function in the adrenal glands.
EFFECT OF GLUCAGON ON BONE COLLAGEN METABOLISM IN THE RAT
Authors: KALU D. N. , HILLYARD CARMEL , FOSTER G. V. 
Published: December 2008

SUMMARY
The effect of glucagon on bone was studied in rats. Urinary hydroxyproline excretion and incorporation of [3H]proline into bone hydroxyproline were used as indices of bone collagen breakdown and formation respectively. Parathyroid extract (15 USP units/rat/h, i.v.), infused into thyroparathyroidectomized animals, increased urinary hydroxyproline excretion. This increase was nullified by simultaneous administration of glucagon (50 μg/rat/h, i.v.). Rats treated with glucagon for 12 days (30 μg/100 g/day, s.c.) excreted slightly less hydroxyproline in their urine than controls. In both intact and thyroparathyroidectomized rats, glucagon (10 μg/100 g/h, s.c.) decreased incorporation of [3H]proline into bone. Similar results were obtained in nephrectomized rats, evidence that changes produced by glucagon were not solely due to alterations in proline pool size caused by increased renal excretion. From these data it is concluded that: (1) glucagon can inhibit bone resorption (the effect being slight in normal rats, but easily demonstrable in parathyroid hormone-treated thyroparathyroidectomized rats), (2) release of endogenous calcitonin is not required to produce this effect, (3) parathyroid hormone and glucagon may act on the same target cell in bone, (4) inhibition of skeletal resorption may contribute to glucagon-induced hypocalcaemia, and (5) the hormone possibly decreases bone formation. Since pharmacological doses of glucagon were used in our studies, the relationship of the observations made to the physiological role of glucagon is unknown.
THE EFFECT OF PROSTAGLANDIN F2α ON PROGESTERONE, OESTRADIOL AND LUTEINIZING HORMONE SECRETION IN SHEEP WITH OVARIAN TRANSPLANTS
Authors: CHAMLEY W. A. , BUCKMASTER JOAN M. , CAIN M. D. , CERINI J. , CERINI MILDRED E. , CUMMING I. A. , GODING J. R. 
Published: December 2008

SUMMARY
The luteolytic properties of prostaglandin F2α (PGF2α) were studied in experiments on sheep with ovarian autotransplants. PGF2α was infused at the rate of 40, 10 and 2 μg/h for 4·0, 7·0 and 9·5–18·0 h respectively. At rates of 40 and 10 μg/h, progesterone secretion decreased to 50% of the control levels in 2·6 ± 1·4 h and fell to 8–30 μg/h within 36–52 h from the start of infusion. The onset of oestrus occurred 42–66 h after the infusions had started and a typical pre-ovulatory surge of luteinizing hormone (LH) was observed 52–66 h after infusing PGF2α. On occasions, this surge was accompanied by a brief peak of oestradiol-17β secretion and shortly thereafter ovarian steroidogenesis decreased to very low levels.
In four sheep infused at a rate of 2 μg/h, peripheral progesterone values decreased gradually and only one animal returned to oestrus. It would seem that 2 μg/h is close to the minimum intra-arterial dose to cause luteolysis in the sheep.
SOME ASPECTS OF THE CONTROL OF DEHYDROEPIANDROSTERONE SYNTHESIS IN THE HUMAN ADRENAL GLAND IN VITRO
Authors: JENSEN VIBEKE , CARSON PAMELA , DESHPANDE N. 
Published: December 2008

SUMMARY
The control of dehydroepiandrosterone (DHA) synthesis in the human adrenal gland was studied by investigating the biosynthesis of its immediate precursor, 17-hydroxypregnenolone (3β,17α-dihydroxy-pregn-5-en-20-one) and the side-chain cleavage. Both conversions take place in the microsomal fraction and there is an obligatory requirement for the co-factor, reduced nicotinamide adenine dinucleotide phosphate (NADPH). Under optimal conditions, 17-hydroxylation is controlled only by the availability of the substrate and the co-factor. By using the same kinetic approach it was observed that the synthesis of DHA is controlled by the availability of substrate and co-factor. However, the reaction was inhibited by the oxidized form (NADP+) and when the ratio of NADP+:NADPH reached 1, the maximum velocity was halved.
Two major metabolites of 17-hydroxypregnenolone, namely DHA and 17-hydroxyprogesterone, are non-competitive inhibitors of the reaction. The inhibition constants are of the magnitude of the tissue concentration of these steroids in the adrenal gland which suggests that non-competitive inhibition takes place in vivo.
THE LOCALIZATION OF PROLACTIN LABELLED WITH RADIOACTIVE IODINE IN RABBIT MAMMARY TISSUE
Authors: BIRKINSHAW MARGARET , FALCONER I. R. 
Published: December 2008

SUMMARY
Study of the removal of 125I-labelled prolactin from the blood of virgin oestrous, pseudopregnant, lactating, weaned and post-partum oestrous rabbits gave a mean half-life of 16·0 ± 1·54 min. No conclusions could be drawn from the results on the influence of physiological condition on half-life. Tissue distribution of 125I-labelled prolactin 60 min after i.v. injection showed that the highest uptake ratio of tissue: plasma was in the kidney, which was confirmed with a concentration of 125I in the urine 6·43 times higher than in the plasma. However, approximately 90% of the 125I in the urine was in the form of labelled products of prolactin degradation. The uptake ratio of mammary tissue: plasma was 2·40 ± 0·09:1 during lactation but was only 0·41 ± 0·04:1 in oestrous rabbits. Of other tissues liver showed the highest ratio of 0·85 ± 0·03:1. The half-life of both 125I- and 131I-labelled prolactin was investigated in vivo in mammary tissue, after i.v. or intraductal injection. No significant differences were seen between methods of administration or differences of isotope, and the average half-life was 52·4 ± 5·9 h.
Autoradiographic studies of the tissue localization of 125I- and 131I-labelled prolactin were carried out, the hormone being administered by i.v. or intraductal injection to 15-day pseudopregnant rabbits, or by incubation with 0·5 mm slices of lactating mammary tissue from rabbits. Samples of tissue were obtained from 10 min to 50 h after administration of labelled hormone. Irrespective of method of administration, isotope or time interval, a selective localization of radioactivity was observed on or near to the alveolar secretory cell membrane, on the side adjacent to the vascular supply. It was concluded that specific sites for labelled prolactin occur in this location, since the opposite side of the alveolar cell membrane adjacent to the duct lumen did not show radioactivity localized on or near it, even when the hormone was administered into the teat ducts.
BIOSYNTHESIS OF HUMAN CHORIONIC GONADOTROPHIN IN VITRO: INCORPORATION OF [14C]l-LEUCINE
Authors: BENAGIANO G. , PALA A. , MEIRINHO M. , ERMINI M. 
Published: December 2008

SUMMARY
Fresh human placental tissue from first trimester pregnancies was incubated with [14C]l-leucine and the incorporation of the labelled amino acid into placental proteins was studied in both the soluble and the particulate fractions. Free [14C]l-leucine was completely separated from labelled proteins by exhaustive dialysis. This was confirmed by Sephadex G-100 gel chromatography.
In preliminary experiments, the total protein fraction from Sephadex was submitted to polyacrylamide gel electrophoresis; columns divided into ten sections were checked, fraction by fraction, for incorporated radioactivity and human chorionic gonadotrophin (HCG) potency, using a radioimmunoassay method. In all instances, the highest HCG activity corresponded to the highest incorporation of radioactivity. In subsequent experiments only those radioactive proteins were used which had the highest activity after chromatography. This peak was further divided into two parts which were submitted to polyacrylamide gel electrophoresis. Using the ascending limb of the peak which contained about 70% of the total HCG activity, there was complete agreement between the distribution of radioactivity and that of HCG activity, whereas the bulk of HCG radioimmunological activity in the descending limb could be dissociated from radioactive proteins.
After absorption of the HCG-like protein with specific anti-HCG serum, HCG activity was completely neutralized and more than 95% of the corresponding radioactivity disappeared. Additional evidence for the presence of an HCG-like biosynthesized protein was obtained after DEAE-cellulose ion exchange chromatography of the products of the incubation. Here again, the HCG potency of the radioactive protein with the highest activity was completely neutralized after absorption with a specific antiserum: in this case, however, only some 60% of the total radioactivity present disappeared after absorption.
The results indicate that human placental tissue can synthesize from l-leucine proteins possessing radioimmunological HCG activity.
ANDROGEN DYNAMICS IN VITRO IN THE CANINE PROSTATE GLAND
Authors: GIORGI ELEONORA P. , GRANT J. K. , STEWART JOAN C. , REID JACQUELINE 
Published: December 2008

SUMMARY
The uptake and metabolism of androgens by canine prostate in vitro were studied by means of an experimental design which consisted of superfusion of prostate slices with a medium containing [4-14C]androstenedione and [6,7-3H]testosterone, or [4-14C]testosterone and 5α-dihydro[1,2-3H]testosterone. The entry or transfer of steroids into the slices, the irreversible metabolism, the conversion between the steroids and their uptake or tissue retention were measured at the steady state. A similar proportion of the three androgens entered the tissue and was irreversibly metabolized. Conversion of testosterone into 5α-dihydrotestosterone was much greater than the interconversion of testosterone and androstenedione. The prostate slices retained 5α-dihydrotestosterone in a concentration up to four times that in the medium, whereas testosterone and androstenedione were retained to a smaller extent.
By increasing the steroid concentration in the perfusing medium from 0·03 to 1·30 μmol/l, it was shown that the systems regulating entry, uptake and metabolism of the androgens were not saturated within this range of concentration. No substantial differences were observed in the regulation of tissue—androgen interaction in vitro between five normal and four hyperplastic canine prostates. This was in contrast with previously reported findings that, in man, normal and hyperplastic prostatic tissue respond in a different way to an increase in steroid concentration in the medium.
CELL DIVISION AND DNA SYNTHESIS IN THE MOUSE UTERUS DURING CONTINUOUS OESTROGEN TREATMENT
Authors: LEE AUDREY E. 
Published: December 2008

SUMMARY
Continuous oestrogen stimulation produced an initial increase in mitosis and [3H]thymidine incorporation in the mouse uterine luminal epithelium on days 2 and 3 of treatment, but activity fell to the level of the untreated uterus on days 4 and 5. The implications of this control of cell division are discussed. A second wave of activity occurred about a week later, and in the longest experiment a third wave was seen on days 19 to 21. This pattern was similar to that seen in the glandular epithelium. There was little cell division in the stroma or myometrium. The rhythm was not due to diurnal variation. It was seen after treatment with oestrone and oestradiol, given either by injection or in the drinking water.
THE EFFECT OF GONADOTROPHINS ON FLUID SECRETION AND SPERM PRODUCTION BY THE RAT AND HAMSTER TESTIS
Authors: SETCHELL B. P. , DUGGAN M. C. , EVANS R. W. 
Published: December 2008

SUMMARY
Single intravenous injections of ovine luteinizing hormone (LH) in adult hamsters and rats had no effect on fluid secretion by the testes, as measured by the gain in weight or water content during a 10-h period after ligation of the efferent ducts (EDL). Neither was there any obvious effect on the liberation of spermatozoa, as judged by the total number of sperm in the unligated and EDL testes and from the concentration of spermatozoa in the secreted fluid, calculated from the difference between the number of sperm in the EDL and unligated testes divided by the difference in weight.
In adult rats treated for 9 weeks with human chorionic gonadotrophin and/or pregnant mare serum gonadotrophin, there was a decrease in sperm production (measured as described above during a 20-h period after EDL) when the two hormones were given together. These treatments, continued for 3 or 9 weeks, had no effect on testicular weight, nor on the secretion of fluid, and the two hormones given together for 9 weeks caused a decrease in the concentration of sperm in collected rete testis fluid. The concentration of spermatozoa in collected rete testis fluid was about one quarter of the calculated concentration in the total secreted fluid.
Ovine follicle-stimulating hormone (FSH) injected daily for 3 days in 21-day-old rats stimulated fluid secretion slightly, and FSH +ovine growth hormone stimulated fluid secretion by the testes of adult rats with oestrogen implants. Ovine LH caused a slight decrease in fluid secretion in oestrogen-treated adults and also in the 21-day-old rats. Ovine prolactin and growth hormone had no significant effect on fluid secretion by the testis in these two groups of rats.
EFFECTS OF OVARIAN STEROID HORMONES ON HISTOCHEMICALLY DEMONSTRABLE LIPIDS IN THE RAT UTERINE EPITHELIUM
Authors: BOSHIER D. P. , HOLLOWAY HILARY 
Published: December 2008

SUMMARY
Histochemical studies showed that during the rat oestrous cycle, uterine epithelial lipids were at their highest levels during dioestrus and pro-oestrus. In ovariectomized mature animals given oestradiol-17β, either by itself or in combination with medroxyprogesterone acetate, neutral lipids and unsaturated lipids were below control levels, while phospholipids were increased. Medroxyprogesterone acetate, however, increased levels of neutral lipids and unsaturated lipids, and decreased phospholipids. It is suggested that during the oestrous cycle of the rat, high concentrations of uterine epithelial lipid during late dioestrus and pro-oestrus reflect the increased plasma progesterone of early dioestrus acting in a low plasma oestrogen environment.
METABOLIC STUDIES IN A PATIENT WITH A PHAEOCHROMOCYTOMA ASSOCIATED WITH HYPOKALAEMIA AND HYPERALDOSTERONISM
Authors: WILSON R. J. , CRAIG GILLIAN M. , MILLS I. H. 
Published: December 2008

SUMMARY
A case of phaeochromocytoma with hypokalaemia, hyperaldosteronism, normal cortisol production and normal urinary corticosteroid excretion is described. Both α-adrenergic blockade and combined α and β blockade resulted in marked antidiuresis with urinary sodium and potassium retention and a rise in plasma volume. Combined α and β blockade led to some reduction in the high aldosterone production rate. The hypokalaemia was corrected by α-adrenergic blockade. After operative removal of the tumour the aldosterone production rate was normal.
The marked reduction in urinary sodium excretion in response to α-adrenergic blockade, if reproducible in other cases of phaeochromocytoma, might be a useful test for the presence of a phaeochromocytoma.