bluuebunny/crossref_metadata_2025_split huggingface dataset:
OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN
Authors: BENTLEY P. J. 
Published: December 2008

SUMMARY
The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small.
Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased.
This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced.
The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present.
The physiological implications of these observations and the possible mechanisms involved are discussed.
EFFECTS OF PROSTAGLANDIN F2α AND E2 ON THE PRODUCTION OF PROGESTERONE BY HUMAN GRANULOSA CELLS IN TISSUE CULTURE
Authors: McNATTY K. P. , HENDERSON K. M. , SAWERS R. S. 
Published: December 2008

SUMMARY
Human granulosa cells with differing steroidogenic potentials were cultured in vitro. The effects of prostaglandin F2α (PGF2α) and PGE2 on the progesterone output and viability of these cells were investigated.
Prostaglandin F2α either alone or in combination with LH and FSH inhibited the production of progesterone over a wide range of concentrations (1–8000 ng/ml). However, the inhibitory effect of PGF2α was 200 times less effective when the cells were exposed to LH and FSH for 6 days before the addition of the prostaglandin. By contrast PGE2, at concentrations from 1 to 500 ng/ml, markedly stimulated the production of progesterone by granulosa cells, and this was not prevented by the addition of PGF2α. The degree of inhibition by PGF2α or stimulation by PGE2 was related to the biosynthetic capacity of the cells.
These studies suggest that PGF2α may act directly on the adenylate cyclase system of human granulosa cells by blocking its activation by LH, and they demonstrate that functional regression of the luteal cell can be induced independently of the blood vascular system.
STUDIES ON PLASMA CORTICOSTEROIDS IN THE RHESUS MONKEY (MACACA MULATTA)
Authors: SETCHELL K. D. R. , SHACKLETON C. H. L. , HIMSWORTH R. L. 
Published: December 2008

SUMMARY
The physiological regulation of the plasma corticosteroid concentration, measured by competitive protein-binding, was studied in female rhesus monkeys (M. mulatta) sedated with phencyclidine hydrochloride. Morning basal levels of plasma corticosteroids were found to be in the range 8·0–25·2 μg/100 ml, which is lower than that previously reported in this species. A circadian rhythm in plasma cortisol concentration was demonstrated. Prolonged sedation with phencyclidine was associated with a gradual increase in the plasma cortisol concentration. Synthetic α1–24 adrenocorticotrophic hormone given intravenously caused a rapid rise in plasma cortisol, the minimum effective dose was between 1 and 10 ng/kg body weight and the response was maximal after 1000 ng/kg. The administration of lysinevasopressin and the induction of hypoglycaemia by insulin were both followed by an increase in the plasma corticosteroid concentration. Metyrapone caused a decline in plasma 11-hydroxycorticosteroids and a concomitant increase in total corticosteroids measured by competitive protein-binding. It is concluded that the hypothalamic-pituitary-adrenal system in the rhesus monkey functions in a manner which is qualitatively and quantitatively similar to that of man.
EFFECT OF ACUTE INHIBITION OF ADRENOCORTICOTROPHIN SECRETION ON PLASMA CORTICOSTEROIDS IN THE RHESUS MONKEY (MACACA MULATTA)
Authors: SETCHELL K. D. R. , REES LESLEY H , HIMSWORTH R. L. 
Published: December 2008

SUMMARY
The half-life of plasma cortisol in the rhesus monkey (M. mulatta), determined by two methods, was about 130 min and longer than that in man; it was unaffected by administration of dexamethasone. Dexamethasone (5 mg, i.v.) immediately inhibited the secretion of ACTH from the monkey pituitary. The plasma half-life of NH2-terminal immunoreactive ACTH was found to be about 55 min which was much longer than the biological half-life. The adrenal synthesis of cortisol was inhibited by metyrapone which caused a prompt increase in the plasma concentration of ACTH and 11-deoxycortisol. The hypothalamicpituitary-adrenal system of the rhesus monkey sedated with phencyclidine hydrochloride responded rapidly to alteration in the level of steroids in the circulation.
PREOVULATORY CHANGES IN THE OVARIES DURING THE FIRST SPONTANEOUS PRO-OESTRUS IN THE RAT
Authors: OSMAN P. 
Published: December 2008

SUMMARY
Events in the ovaries during the first spontaneous pro-oestrus were compared with those in the adult rat. The occurrence of first spontaneous pro-oestrus was determined from vaginal smears after surgical opening of the vagina. Pubertal rats showed a remarkable increase in ovarian weight from 10.00 to 15.00 h on the day of pro-oestrus, which was absent in the adults. They also showed an earlier and more pronounced interstitial oedema. Dispersion of cumulus cells, resumption of meiosis and ovulation also occurred slightly earlier in pubertal rats. A distinct difference was found in the growth rate of follicles of ovulatory size, i.e. follicles of ≥ 500 × 105 μm3. At the first pro-oestrus these follicles showed a slower and less pronounced increase in size from 10.00 to 17.00 h compared with the adult follicles at this time, although this disparity was made up by a marked increase in growth from 17.00 to 24.00 h. The development of a new crop of follicles progressed similarly in the pubertal and adult animals. Follicular atresia seemed to progress more rapidly from 10.00 to 15.00 h in the pubertal animals compared with adults but from 15.00 h onwards no further differences were observed. The possible causal factors underlying the observed differences between the pubertal and adult animal are discussed.
AN UNUSUAL PATTERN OF TESTOSTERONE METABOLISM IN TISSUE ASSOCIATED WITH A KERATIN-FILLED CUTANEOUS CYST
Authors: HAY J. B. , HODGINS M. B. 
Published: December 2008

SUMMARY
Testosterone metabolism was studied in tissues associated with a keratin-filled cutaneous cyst. Instead of the 5α-reduced metabolites usually associated with skin steroid metabolism, considerable amounts of 5β-reduced steroids were found. These included 5β-androstane-3,17-dione, 17β-hydroxy-5β-androstan-3-one, and 5β-androstane-3β,17β-diol. This change in metabolic pattern is discussed.
GONADOTROPHIN AND STEROID LEVELS AROUND THE TIME OF FIRST OVULATION IN THE RAT
Authors: MEIJS-ROELOFS H. M. A. , UILENBROEK J. TH. J. , DE GREEF W. J. , DE JONG F. H. , KRAMER P. 
Published: December 2008

SUMMARY
Luteinizing hormone, FSH, prolactin, oestradiol and progesterone concentrations were measured by radioimmunoassay in the blood of female rats from 7 days before the first ovulation (the day of first ovulation is designated day 0) until the day after the second ovulation. Serum LH concentrations varied between 29 and 59 ng NIAMDD-rat-LH RP-1/ml from days −7 to −2. On the day preceding first ovulation (day − 1) a steep increase in serum LH was found between 13.00 h and 15.00 h reaching a maximal value of 2100 ng/ml at 17.00 h. Thereafter LH levels decreased to undetectable values (< 15 ng/ml). Serum FSH concentrations from days −7 to −2 varied between 108–154 ng NIAMDD-rat-FSH RP-1/ml; increased concentrations were found on the afternoon of day − 1 and on the morning thereafter (first oestrus) with a maximal value of 1150 ng/ml at 19.00 h on day − 1. On the day preceding the second ovulation (day +4) LH and FSH peaks were again found.
Prolactin concentrations on the days preceding first ovulation were generally low. A small rise was found nearing first ovulation (12·7 ng/ml, day −6; 23·9 ng/ml, day −2). On day − 1 a peak (118 ng/ml) was found at 15.00 h, similar to that found on day +4 in adult pro-oestrous rats.
Plasma progesterone concentrations also reached a peak value (50 ng/ml) on day − 1, at 17.00 h, preceded by concentrations between 3–5 ng/ml from days −6 to −2. Progesterone concentrations after the first ovulation showed a pattern characteristic of the adult cycle.
Plasma oestradiol levels were undetectable (< 10 pg/ml) from days −6 to −2; a clearly increased oestradiol concentration was found on day −1, reaching a value of 98 pg/ml. One and two days before the second ovulation, oestradiol levels rose again.
The differences and similarities between pubertal and adult pro-oestrous hormone peaks are discussed.
ENZYME ACTIVITY IN KIDNEY, ADRENAL AND GONADAL TISSUE OF RATS TREATED NEONATALLY WITH ANDROGEN OR OESTROGEN
Authors: GHRAF R. , HOFF H.-G. , LAX E. R. , SCHRIEFERS H. 
Published: December 2008

SUMMARY
A single injection of 300 μg oestradiol benzoate (OEB) or 1·25 mg testosterone propionate (TP) on day 1 of life led to significant changes in the activity of enzymes involved in steroid hormone metabolism in kidney, adrenal and gonadal tissues of adult rats. In the kidney, the enzyme activities of male rats reacted to OEB, but not TP, by the development of normal female levels. With one exception the enzyme activities of the kidney of female rats did not respond to either steroid. In the adrenal of both sexes 5α-reductase reacted to OEB, but not TP treatment, by a fourfold increase in activity. In the ovary all the enzymes investigated responded both to OEB and TP treatment by a fall in activity; 20α-hydroxysteroid dehydrogenase activity fell to undetectable levels. In the testis, OEB and TP treatment led to contrasting effects. With the exception of 5α-reductase all the enzymes tested in this organ responded to OEB by a rise in activity. Where TP had any effect, it produced a slight decrease in activity.
EFFECT OF l-DOPA ON MILK EJECTION AND PROLACTIN RELEASE IN LACTATING RATS
Authors: PRILUSKY J. , DEIS R. P. 
Published: December 2008

SUMMARY
The effect of l-DOPA on milk ejection and on prolactin release during 30 min of suckling was studied in lactating rats. Various doses of l-DOPA (1·25, 2·5, 5 and 10 mg/100 g body wt) were injected i.p. 30 min before the suckling period. Control rats were injected with 0·9% NaCl solution only. An inhibition of milk ejection proportional to the dose of drug administered was obtained. The dose of 10 mg completely blocked milk ejection but 1·25 mg had no effect. A normal milk-ejection response was obtained with a small dose of oxytocin injected immediately before nursing into mothers treated with 10 mg l-DOPA, indicating that the blocking effect was not due to a lack of mammary gland response. In control mothers, serum prolactin levels increased from 67·2 ± 25·9 (s.e.m.) to 950·3 ± 118·7 ng/ml after a 30 min suckling period. l-DOPA (5 and 10 mg) prevented the release of prolactin induced by suckling, but 1·25 and 2·5 mg l-DOPA had no effect. The results indicate that oxytocin and prolactin release induced by suckling in lactating rats is inhibited by an increase of catecholamines at the hypothalamic-hypophysial axis.
INTERRELATIONSHIPS OF PITUITARY AND PLASMA CORTICOTROPHIN AND PLASMA CORTICOSTERONE DURING ADRENOCORTICAL REGENERATION IN THE RAT
Authors: BUCKINGHAM JULIA C. , HODGES J. R. 
Published: December 2008

SUMMARY
Pituitary and plasma ACTH and plasma corticosterone were measured at various times after adrenal enucleation or adrenalectomy. The changes in ACTH could be inversely correlated with those in plasma corticosterone. They could also be prevented by maintenance therapy with the steroid. The results indicate that the corticosteroids control both the release and the synthesis of ACTH but that their effect is predominantly on the release of the hormone.
CORTICOSTEROID BINDING BY PLASMA PROTEINS AND THE EFFECTS OF OESTROGENS IN THE MARSUPIAL BRUSH-TAILED OPOSSUM, TRICHOSURUS VULPECULA (KERR)
Authors: THAN KHIN AYE , McDONALD I. R. 
Published: December 2008

SUMMARY
Using the techniques of equilibrium dialysis at 36 °C and gel filtration at 4 °C, a highaffinity, transcortin-like, corticosteroid binding system has been demonstrated in the blood plasma of the marsupial Trichosurus vulpecula.
The affinity constant for non-albumin binding was 4·018 ± 1·032 × 107 (s.d.) 1/mol for males and 4·046± 0·981 × 107 for females. The concentration of non-albumin binding sites was 1·82 ± 0·76 × 10−7 mol/l in males and 1·86 ± 0·57 × 10−7 mol/l for females. Oestrogen administration, sufficient to cause marked hypertrophy of the genital tract in the females, had no effect on the affinity constant or the concentration of the non-albumin binding sites in either males or females.
The general condition of the animals deteriorated during oestrogen administration and there were significant falls in the concentrations of albumin and cortisol in the blood plasma. In one animal which died during oestrogen treatment, the adrenal glands were significantly hypertrophied.
A POSSIBLE ROLE FOR OXYTOCIN IN SPERM TRANSPORT IN THE MALE RABBIT
Authors: SHARMA O. P. , HAYS R. L. 
Published: December 2008

SUMMARY
Administration of methallibure (50 mg/kg body weight, daily) to male rabbits resulted in a 45% reduction in sperm number in ejaculates obtained during the treatment period. Recovery occurred within 48 h after the last dose of methallibure. This decrease in sperm number did not occur when oxytocin (0·2 i.u./kg body weight) was administered simultaneously with methallibure. This suggests that methallibure prevents the release of oxytocin during ejaculation.
FURTHER EVIDENCE FOR HISTAMINE FACILITATING OESTROGEN ACTION IN THE UTERUS
Authors: CASTRO-VÁZQUEZ A. , GÓMEZ ELENA , DE CARLI D. N. , ROSNER J. M. 
Published: December 2008

SUMMARY
The effect of doses of oestradiol ranging from 0·0125 to 1·6 μg on the uterine weight of the spayed rat was studied 24 h after a single s.c. injection of the hormone. The lowest dose inducing a significant increase in uterine weight was 0·32 μg. When histamine dihydrochloride (50 mg) was simultaneously injected with the hormone, the effect of small doses of oestradiol (0·0125–0·2 μg) was significantly increased.
When oestradiol and histamine were administered for 3 successive days, the uterine weight of animals receiving 0·0125 μg oestradiol, if compared with untreated controls, was increased only in the histamine-treated group. When 0·05 μg oestradiol was administered, histamine did not modify the increase already produced by the hormone.
Spermidine and burimamide, two substances structurally related to histamine, increased [3H]oestradiol uptake by the spayed rat uterus. The latter (an antihistamine drug acting on H2-receptors) as well as pyrathiazine (a histamine releaser having antihistamine properties) decreased the effect of histamine on oestradiol uptake whereas diphenhydramine (an antihistamine drug blocking H1-receptors) did not modify it. Pyrathiazine was itself able to diminish oestradiol uptake.
MEASUREMENT OF CORTISOL, CORTISONE, 11-DEOXYCORTISOL AND CORTICOSTERONE IN FOETAL SHEEP PLASMA DURING THE PERINATAL PERIOD
Authors: THOMAS S. J. , WILSON D. W. , PIERREPOINT C. G. , CAMERON E. H. D. , GRIFFITHS K. 
Published: December 2008

SUMMARY
A method is described for the resolution and individual quantitation of cortisol, cortisone, 11-deoxycortisol and corticosterone in foetal sheep plasma. The steroids were extracted by solvent partition and separated by LH-20 Sephadex column chromatography. Radioimmunoassay was used for the measurement of 11-deoxycortisol and cortisone and competitive protein-binding for corticosterone and cortisol.
The relative levels of these steroids in the plasma of chronically catheterized sheep foetuses from 12 days before birth to term and then in the newborn lamb until 2 days of age are recorded.
Cortisol gradually increased from a basal concentration of between 0·5 and 3·0 μg/100 ml plasma between days 12 and 5 pre partum, and then rose rapidly to 10 μg/100 ml plasma during the last 5 days of pregnancy to reach a maximum during or just after birth. Two days post partum the levels had fallen to approximately 3 μg/100 ml plasma.
The mean value for 11-deoxycortisol between days 8 and 3 pre partum was 0·4 μg/100 ml plasma and increased in the final days before delivery to 1·0 μg/100 ml. Corticosterone initially showed slightly higher levels (∼ 1·5 μg/100 ml) in the earlier period of investigation but then fell during the immediate pre-partum period to 0·8 μg/100 ml. Cortisone was not detected at any stage of the investigations.
The relationship between levels of cortisol and 11-deoxycortisol in foetal plasma and myometrial contractility is shown. An increase in uterine activity was seen to occur at the time that cortisol levels were at their maximum. The 11-deoxycortisol values throughout this particular study remained low.
The results are discussed in relation to recorded levels in the adult and to previous studies in vitro with regard to changing steroid biosynthetic enzyme activity.
DISTRIBUTION OF NEUROSECRETORY GRANULES AMONG THE ANATOMICAL COMPARTMENTS OF THE NEUROSECRETORY PROCESSES OF THE PITUITARY GLAND: A QUANTITATIVE ULTRASTRUCTURAL APPROACH TO HORMONE STORAGE IN THE NEURAL LOBE
Authors: MORRIS J. F. 
Published: December 2008

SUMMARY
The distribution of neurosecretory granules in various anatomical compartments of neurosecretory axons of the neural lobe of the rat pituitary has been studied. Apart from the most anterior tip of the gland, where granules are largely restricted to undilated axons and a few 'swellings', the proportional compartmental storage of granules is essentially homogeneous for the rest of the gland: 13% of granules are found in undilated axons, 31% in axonal 'endings' (which contain microvesicles and abut the basement membrane) and 55% in axonal 'swellings' (which are devoid of significant numbers of microvesicles). These values indicate that the 'endings' contain a much greater proportion of the total number of granules stored in the neural lobe than would be predicted if the readily releasable pool of hormone were composed of all the granules in the 'endings'. Some further constraint on granule release either physiological or anatomical (e.g. the position of the granule in relation to the plasmalemma of the 'ending') must be operative.
EFFECT OF INTRA-UTERINE BEADS ALONE, OR COMBINED WITH OESTROGEN TREATMENT, ON UTERO-OVARIAN VENOUS PLASMA PROSTAGLANDIN F2α AND PROGESTERONE LEVELS IN THE GUINEA-PIG
Authors: BLATCHLEY F. R. , DONOVAN B. T. , POYSER N. L. 
Published: December 2008

SUMMARY
The presence of beads in the guinea-pig uterus caused premature regression of the corpora lutea, and a corresponding decrease in utero-ovarian venous plasma levels of progesterone, by days 9–10 of the oestrous cycle. If the beads were placed in one horn only, premature luteal regression occurred only in the adjacent ovary. Induced luteal regression was preceded by an increased release of prostaglandin F2α (PGF2α) from the uterine horns which contained the beads.
Oestradiol benzoate treatment of guinea-pigs carrying beads in one uterine horn overcame the unilateral effect and resulted in premature luteal regression in both ovaries. This was also associated with the early release of PGF2α from both uterine horns, though a difference in the timing of the release was apparent between the bead-containing (experimental) and control horns.
EFFECTS OF NEW MULTI-SITE HORMONE BLOCKERS ON THE FERTILITY OF MALE RATS
Authors: GOLDMAN A. S. , SHAPIRO B. H. , ROOT A. W. 
Published: December 2008

SUMMARY
The effects on the fertility of adult male rats of six new synthetic steroids: I, 3-cyano-5α-androst-l-en-17-one; II, the 17β-acetate form of I; III, 17β-hydroxy-5β-cyano-androstan-3-one; IV, 6-methylpregnenolone; V, 17β-hydroxy-17α-ethynyl-5β-cyano-19-norandrostan-3-one; and VI, 19-norspiroxenone (oestr-4-en-3-one-spiro-17α-2′-[tetrahydrofuran]) have been tested. After 6 weeks of treatment with daily doses of 5 mg (I, II, III), 15 mg (IV) or 10 mg (V, VI) only steroid VI blocked the completion of spermatogenesis and reduced the number of foetuses sired in at least five females/male. Steroid VI also diminished seminal vesicular, prostatic, testicular and epididymal weights. It inhibited the testicular enzymes, 3β-hydroxysteroid dehydrogenase-Δ4–5-3-oxosteroid isomerase system, 17α-hydroxylase, and C17–20 lyase markedly, but did not affect the adrenal dehydrogenase–isomerase system. It depressed, strikingly, testicular and serum levels of testosterone and 5α-dihydrotestosterone and reduced pituitary and serum levels of FSH and LH. Although marked depression of target organ weights also occurred with steroids II, IV and V, and reduction of androgen levels and LH in the circulation with III, IV and V, only VI was a potent blocker of male fertility with the exception of a slight block of the siring of viable foetuses by steroids IV and V. The major difference in site of action of steroid VI from the others was the depression of pituitary and serum levels of FSH along with a marked diminution of testicular content of both testosterone and 5α-dihydrotestosterone. 19-Norspiroxenone in the rat is a potent anti-oestrogen without inherent oestrogenicity and is anti-uterotrophic. Thus, VI may affect male fertility by virtue of its potent anti-oestrogenic action in the hypothalamus or testis.
RNA AND PROTEIN METABOLISM IN THE OVIDUCT AND ENDOMETRIUM OF THE EWE AT PRO-OESTRUS: REGULATION BY OESTRADIOL AND PROGESTERONE
Authors: MILLER B. G. 
Published: December 2008

SUMMARY
The effects on RNA and protein metabolism in the oviduct and endometrium at pro-oestrus of oestradiol and progesterone secreted during the oestrous cycle were examined, using the ovariectomized, hormone-treated ewe as a model system. Thirty ewes received hormone injections during a period of 13 days, according to schedules designed to simulate endogenous ovarian secretion of oestradiol and progesterone during the oestrous cycle. Hormone effects on RNA:DNA ratios and on rates of synthesis of protein and methylated RNA in vitro, as well as effects on oviducal and uterine weight, were examined.
The results obtained suggest that endogenous ovarian hormones have the following effects in the intact ewe. The secretion of oestradiol at pro-oestrus rapidly increases rates of synthesis of protein and methylated RNA, and mean cell content of RNA in both the endometrium and oviduct. Oestradiol secreted during the previous luteal phase of the oestrous cycle markedly increases mean cell content of RNA and amounts of protein and methylated RNA synthesis occurring in both tissues at pro-oestrus. In the endometrium, progesterone secreted during the luteal phase increases the RNA: DNA ratio, and probably also the amounts of protein and methylated RNA synthesized at pro-cestrus, but there are no significant interactions between the effects of oestradiol and progesterone. Progesterone had no effect on either the amounts or rates of synthesis of protein or methylated RNA in the oviduct. The results are discussed in relation to the hormonal regulation of physiological functions of the oviduct and endometrium during the first few days after the onset of oestrus.