bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF DIBUTYRYL CYCLIC AMP ON THE RELEASE OF MELANOCYTE-STIMULATING HORMONE FROM RAT NEUROINTERMEDIATE LOBES IN VITRO
Authors: BAKER BRIDGET I. 
Published: December 2008

SUMMARY
A method for measuring melanocyte-stimulating hormone (MSH) in rat neurointermediate lobe in vitro and in incubation medium, using polyacrylamide gel electrophoresis, is described. Using this technique, it was shown that dibutyryl cyclic AMP increased the release of MSH in vitro, the degree of stimulation depending on the concentration of the nucleotide. The effect of low concentrations of the nucleotide was potentiated by theophylline.
LEVELS OF FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE, OESTRADIOL-17β AND PROGESTERONE, AND FOLLICULAR GROWTH IN THE PSEUDOPREGNANT RAT
Authors: WELSCHEN R. , OSMAN P. , DULLAART J. , DE GREEF W. J. , UILENBROEK J. TH. J. , DE JONG F. H. 
Published: December 2008

SUMMARY
Throughout a period of pseudopregnancy the peripheral blood levels of progesterone, oestradiol-17β, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), as well as the size-distribution of ovarian antral follicles were estimated in the rat. The progesterone concentrations, as measured by a competitive protein-binding technique, exceeded metoestrous values (25 ng/ml plasma) from day 3 of pseudopregnancy onwards. The highest levels were found on days 6 and 8 (91 ng/ml). From day 8 onwards the levels decreased gradually but were still above metoestrous values on the day of pro-oestrus after pseudopregnancy. Concentrations of oestradiol-17β, as measured by radioimmunoassay, were within the range of those at metoestrus (about 5 pg/ml plasma) until day 10. Thereafter levels increased to a value of 57 pg/ml.
Concentrations of FSH, measured by radioimmunoassay, were within the range of metoestrous values until day 10 (about 100 ng NIAMD-rat-FSH RP-1/ml serum), but declined to a level of 33 ng/ml on day 12. Concentrations of LH, measured by radioimmunoassay, were generally within the wide range of metoestrous values (9–60 ng NIAMD-rat-LH RP-1/ml serum), but concentrations found on days 4, 8 and 10 were significantly lower than those found on preceding or subsequent days.
Histological determination of the number of follicles present in various volume-classes, showed an increase in antral follicles on days 1 and 2, comparable to the increase observed during metoestrus and dioestrus 1 of the normal cycle. There was no change in the follicles between days 3 and 10 and they resembled those of early dioestrus. Preovulatory growth had occurred by day 12. Injection of human chorionic gonadotrophin (HCG) on days 2, 4 or 6 showed that ovulation could be induced only in some of the larger follicles.
On the basis of these results it is suggested that during pseudopregnancy the high progesterone levels present result in a decreased plasma LH level which is insufficient to cause full maturation of the follicles and to stimulate oestrogen secretion to the levels required for induction of an ovulatory surge of LH release.
RELATIVELY GREATER INCREASE OF OXYTOCIN THAN VASOPRESSIN IN THE SUPRAOPTIC NUCLEUS OF RATS AFTER HYPOPHYSECTOMY
Authors: DYBALL R. E. J. , HENRY JUDITH A. 
Published: December 2008

SUMMARY
The vasopressor and milk ejection activities were estimated in the supraoptic region of the hypothalamus of rats which had been hypophysectomized 30 min, 4 and 8 days earlier. Both pressor and milk ejection activities were significantly greater 4 days after hypophysectomy than those in sham-operated control rats. Eight days after hypophysectomy, pressor activity decreased below control values but milk ejection activity was still significantly raised. Increased biological activity after hypophysectomy is thus associated with the previously observed increase in neurosecretory material within the supraoptic nucleus so these results provide additional evidence that neurosecretory material represents stored hormone. Milk ejection activity increased relatively more than pressor activity which supports the suggestion that the final stage in the formation of neurohypophysial hormones occurs as they pass from the hypothalamus to the neural lobe. If this final maturation normally occurs more slowly for oxytocin than for vasopressin, the obstruction to the flow of hormones down the neural stalk caused by hypophysectomy would result in a greater increase in milk ejection than pressor activity.
SUPERFUSION IN VITRO IN THE STUDY OF OVARIAN STEROIDOGENESIS
Authors: WATSON JOHN , LEASK J. T. S. 
Published: December 2008

SUMMARY
A method for the continuous superfusion of porcine corpus luteum tissue is described which readily allows both the introduction of regulatory factors to the incubating tissue, and sampling of the tissue. Oestrogen (principally oestradiol) and progestin (principally progesterone) can be measured for up to 24 h in the superfusate from corpora lutea of all ages, and the secretion of both steroids is stimulated by the addition of luteinizing hormone. The pattern of response of both steroids to a pulse of gonadotrophin was similar in that a rapid transient increase in secretion occurred followed some time later by a secondary and more prolonged response. A second pulse of gonadotrophin introduced 6 h after the first also stimulated steroid secretion, indicating that during superfusion in vitro the porcine corpus luteum does not become refractory to the steroidogenic effect of gonadotrophin.
EFFECTS OF HYPOTHALAMIC EXTRACT AND DIBUTYRYL CYCLIC ADENOSINE MONOPHOSPHATE ON FOLLICLE-STIMULATING HORMONE PRODUCTION IN THE RAT ADENOHYPOPHYSIS IN VITRO
Authors: DAVIS J. C. , HYMER W. C. 
Published: December 2008

SUMMARY
An assay system, using the characteristic migration of follicle-stimulating hormone (FSH) on polyacrylamide gels, was developed to evaluate the effects of hypothalamic factors on amino acid incorporation into FSH in the rat adenohypophysis incubated in vitro. Follicle-stimulating hormone extracted from rat pituitary secretory granules was found to migrate on 7·5% polyacrylamide gels, pH 9·5, as a protein with an RF of 0·614. The characteristic RF was used to measure [14C]amino acid incorporation into FSH in rat adenohypophyses in vitro. Follicle-stimulating hormone synthesis increased after addition of crude hypothalamic extract to the incubation medium. Hormone synthesis was also increased three times after the addition of dibutyryl cyclic AMP.
PARTIAL FEMINIZATION OF HEPATIC STEROID METABOLISM IN MALE RATS AFTER NEONATAL ADMINISTRATION OF CYPROTERONE ACETATE
Authors: GUSTAFSSON JAN-ÅKE , INGELMAN-SUNDBERG MAGNUS , STENBERG ÅKE , NEUMANN FRIEDMUND 
Published: December 2008

SUMMARY
The metabolism of [4-14C]4-androstene-3, 17-dione, [4-14C]5α-androstane-3α, 17β-diol and 1,2-3H]5α-androstane-3α, 17β-diol 3,17-disulphate was studied using the microsomal fraction and the metabolism of [4-14C]4-androstene-3, 17-dione was studied using the 105 000 g supernatant fraction of liver from male and female rats aged 5 months that had been treated with cyproterone acetate before (from day 13 of pregnancy) and after birth (until 3 weeks of age). Nearly all sex-dependent enzyme activities in the treated male rats were changed in a direction characteristic of female rats: 5α-reductase active on 4-androstene-3, 17-dione increased in activity whereas 3β- and 17α-hydroxysteroid reductases and 6β- and 16α-hydroxylases active on 4-androstene-3, 17-dione and 2α-, 2β- and 18-hydroxylases active on 5α-androstane-3α, 17β-diol decreased in activity. Enzyme activities not under gonadal control, i.e. 3α- and 17β-hydroxysteroid reductases active on 4-androstene-3, 17-dione and 7α-hydroxylase active on both 4-androstene-3, 17-dione and 5α-androstane-3α, 17β-diol, were not affected by cyproterone acetate. The liver enzyme activities in treated female rats were generally not affected although significant effects were noted in two cases; in one of these (17α-hydroxysteroid reductase) a testosterone-like effect was observed.
The results obtained are probably best explained in the following way: treatment with the anti-androgen during the neonatal period results in less efficient imprinting of the hypothalamo-hypophysial system leading to less pronounced masculine setting of sex-dependent enzyme levels and also to a relative androgen unresponsiveness. It is suggested that the biochemical methods used in the present investigation may be used for more exact estimation of the degree of neonatal sexual differentiation of the hypothalamo-hypophysial system than biological and psychological methods previously available.
ESTIMATION OF ALDOSTERONE, 11-DEOXYCORTICOSTERONE, 18-HYDROXY-1 1-DEOXYCORTICOSTERONE, CORTICOSTERONE, CORTISOL AND 11-DEOXYCORTISOL IN HUMAN PLASMA BY GAS–LIQUID CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION
Authors: MASON P. A. , FRASER R. 
Published: December 2008

SUMMARY
A method for determining the plasma concentrations of six major corticosteroids, aldosterone, 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), corticosterone, deoxycorticosterone (DOC), cortisol and 11-deoxycortisol using gas–liquid chromatography with electron capture detection is described. Esterification of suitable derivatives of these compounds with heptafluorobutyric anhydride (HFB) allowed detection of quantities of steroid, ranging from 0·3 pg for androstenetrione HFB (from cortisol) to 2·3 pg for corticosterone HFB. No detectable reagent blank was obtained for any compound when water was used instead of plasma and this was also the case when plasma from an adrenalectomized subject was analysed, with the exception of 18-OH-DOC where a reproducible but negligibly small blank occurred. Coefficients of variation for replicate determinations ranged from 8% for corticosterone to 17% for aldosterone. Concentrations in a series of normal human plasma samples were as follows: aldosterone, 4·0–18·0 ng/ 100 ml; 18-OH-DOC, 20–160 ng/ml; corticosterone, 0·08–0·80 μg/100 ml; DOC, 2·8–16·0 ng/100 ml; cortisol, 2·5–10·0 μg/100 ml;and 11-deoxycortisol, 40·0–400·0 ng/100 ml. When seven normal subjects were treated with dexamethasone, concentrations of DOC, cortisol and 11-deoxycortisol fell to below the limit of the normal range, those of 18-OH-DOC and corticosterone were at the lower end of the normal range while the concentration of aldosterone was not significantly affected.
PLASMA PROGESTERONE AND ITS RELATIONSHIP TO SERUM GONADOTROPHINS IN IMMATURE FEMALE RATS
Authors: MEIJS-ROELOFS H. M. A. , DE GREEF W. J. , UILENBROEK J.TH.J. 
Published: December 2008

SUMMARY
In immature female rats, low values for concentrations of plasma progesterone were generally found from days 6–15 and from days 25–32 of life. Maximum progesterone concentrations (13·0–14·1 ng/ml), comparable to metoestrous values in the adult rat, occurred on days 20–22. The progesterone appeared to be of ovarian origin since after ovariectomy, on day 18, low progesterone concentrations were found 1 and 2 days later (2·5 ng/ml and 1·3 ng/ml) as compared with control values of 10·7 ng/ml and 14·1 ng/ml. However, adrenalectomy also lowered progesterone concentrations, 1 and 2 days later (6·4 and 4·9 ng/ml).
The effect of progesterone, either alone or in combination with oestradiol benzoate (OB), on serum gonadotrophins was studied in rats ovariectomized on day 18. The highest dose of progesterone (0·15 mg) only slightly diminished the rise in serum luteinizing hormone (LH) after ovariectomy and had no effect on serum follicle-stimulating hormone (FSH).
Oestradiol benzoate in a dose of 0·025 μg/100 g body weight was highly effective in preventing the rise in both LH and FSH concentrations, and OB treatment (resulting in a near-physiological oestradiol concentration) combined with progesterone treatment was more effective than treatment with OB alone.
The results suggest that the amounts of progesterone and oestradiol present in the 20-day-old rat are adequate to cause the decrease in FSH level normally observed in immature female rats around this age.
CHANGES IN THE CONCENTRATION OF PITUITARY AND STEROID HORMONES IN THE FOLLICULAR FLUID OF HUMAN GRAAFIAN FOLLICLES THROUGHOUT THE MENSTRUAL CYCLE
Authors: McNATTY K. P. , HUNTER W. M. , McNEILLY A. S. , SAWERS R. S. 
Published: December 2008

SUMMARY
The concentrations of FSH, LH, prolactin, oestradiol and progesterone were measured in peripheral plasma and follicular fluid of women throughout the menstrual cycle. With the exception of prolactin, concentrations of pituitary and steroid hormones in follicular fluid correlated with those in peripheral plasma.
Follicle-stimulating hormone was present in a greater number of small follicles ( < 8 mm) during or just after the peaks of FSH in peripheral plasma. During the mid-follicular phase the concentration of both FSH and oestradiol in fluid from large follicles ( ≥ 8 mm) was high. During the late follicular phase the large follicles ( ≥ 8 mm) contained high amounts of progesterone in addition to oestradiol, low physiological levels of prolactin, and concentrations of LH and FSH about 30 and 60% respectively of those found in plasma. By contrast no large 'active' follicles ( ≥ 8 mm) were found during the luteal phase although many contained both LH and FSH. Luteinizing hormone was present in a proportion of small follicles ( < 8 mm) during the late follicular and early luteal but not at other stages of the menstrual cycle.
It is suggested that a precise sequence of hormonal changes occur within the microenvironment of the developing Graafian follicle; the order in which they occur may be of considerable importance for the growth of that follicle and secretory activity of the granulosa cells both before and after ovulation.
A COMPARISON OF THE EFFECTS OF THE CALCITONINS, STEROID HORMONES AND THYROID HORMONES ON THE RESPONSE OF BONE TO PARATHYROID HORMONE IN TISSUE CULTURE
Authors: ATKINS D. , PEACOCK M. 
Published: December 2008

SUMMARY
A bone culture system was used to compare the effects of several hormones on the response of 5-day-old mouse calvaria to parathyroid hormone (PTH). The results showed that salmon calcitonin was almost 105 times more active than any other hormone in preventing the PTH-induced release of calcium and caused a dose-related inhibition of calcium release over a range of 0·2–200 milli MRC units/culture. A high dose of calcitonin (200 milli MRC units) caused a net accretion of calcium in the absence of PTH. Progesterone and testosterone were more active than the naturally occurring oestrogens although a synthetic oestrogen (stilboestrol diphosphate) had approximately the same potency. High concentrations of these hormones caused a net accretion of calcium whether or not PTH was present. Cortisol was only effective at high doses, as was the steroid precursor cholesterol. In the present culture system the thyroid hormones (triiodothyronine and thyroxine) inhibited the action of PTH.
It was concluded that these agents acted in a similar fashion to the oestrogens. That is, they prevented the accumulation of citric acid induced by PTH by reducing the rate of glycolysis. None of the hormones affected the inhibition of citrate oxidation caused by PTH.
The results also showed that, whilst these hormones inhibited PTH-mediated bone resorption, they had an action on bone independent of PTH. Experiments with clomiphene citrate failed to demonstrate an oestrogen receptor in bone.
RELEASE OF CORTICOTROPHIN RELEASING FACTOR AND OTHER HYPOPHYSIOTROPIC SUBSTANCES FROM ISOLATED NERVE-ENDINGS (SYNAPTOSOMES)
Authors: BENNETT G. W. , EDWARDSON J. A. 
Published: December 2008

SUMMARY
Synaptosomes isolated from the sheep and the rat hypothalamus contain corticotrophin releasing factor, vasopressin, prolactin-release inhibiting factor and probably all of the substances which participate in the regulation of adenohypophysial function. Electrical field stimulation or depolarizing concentrations (55 mmol/l) of potassium ions cause a release of these factors from the incubated nerve-endings in a calcium-dependent manner. It is suggested that synaptosomes may provide a valuable approach to the study of mechanisms involved in hypothalamic neurosecretion in vitro.
OESTRADIOL-INDUCED SYNTHESIS OF A SPECIFIC UTERINE PROTEIN IN PROPRANOLOL-TREATED RATS
Authors: DUPONT-MAIRESSE N. , GALAND P. 
Published: December 2008

SUMMARY
While there is conflicting evidence concerning an effect of oestradiol on uterine cyclic AMP concentration, results from different laboratories (including ours) are in agreement that even when observed, the early increase in uterine cyclic AMP after oestradiol injection fails to occur when propranolol, a β-adrenergic blocking agent, is given (50 μg, i.p.) 20 min before the oestradiol.
The present work shows that pretreatment with propranolol failed to inhibit an early uterine response to oestradiol, namely the synthesis after 1 h of uterine protein, or class of proteins, IP. It is concluded that the induction of IP by oestradiol does not depend on an increase in uterine cyclic AMP concentration and that β-adrenergic receptors do not have a role in this oestrogenic response.
5α-DIHYDROTESTOSTERONE STIMULATION OF HUMAN PROSTATE IN ORGAN CULTURE
Authors: GHANADIAN R. , CHISHOLM G. D. , ANSELL I. D. 
Published: December 2008

SUMMARY
Explants of human benign hypertrophied prostate were cultured for 8 days. The effect of 5α-dihydrotestosterone on the morphology, DNA and glucose utilization of 14 cases was investigated. In four cases proliferation was clearly more extensive in the dihydrotestosterone-treated explants than in the controls. In six explants, there were no morphological differences between those cultured with or without dihydrotestosterone and in half of these, proliferation was present. Four explants were either necrotic or did not contain epithelial cells. The mean DNA content of the treated explants was higher than that of the controls (P < 0·01). There was no significant difference in the rate of glucose utilization by the explants treated with dihydrotestosterone, and by the controls.
ANDROGENIC REGULATION OF RAPIDLY SYNTHESIZED RNA IN THE RAT VENTRAL PROSTATE
Authors: HONMA YOSHIO , NOUMURA TETSUO 
Published: December 2008

SUMMARY
The influence of castration on the incorporation of nucleotide precursors into RNA of isolated prostatic tissue has been investigated. Castration brought about an apparent increase of incorporation by increasing the specific activity of the uridine nucleotide pool and not by an enhancement in synthesis of rapidly labelled RNA. An actual decrease in this reaction was shown by dividing the radioactivity incorporated into RNA by the specific activity of the uridine nucleotide. Administration of testosterone brought about enhanced synthesis of RNA in the prostates of rats castrated for 3 days as early as 4 h after injection, reaching maximum effect at 8 h. No significant difference was found between the turnover rates of rapidly labelled RNA from castrated, androgen-treated castrated and intact rats. The increased prostatic permeability to nucleosides as an early action of androgens in this organ is discussed.
A RADIOIMMUNOASSAY FOR PLASMA ARGININE-VASOPRESSIN IN MAN AND DOG: APPLICATION TO PHYSIOLOGICAL AND PATHOLOGICAL STATES
Authors: MORTON J. J. , PADFIELD P. L. , FORSLING MARY L. 
Published: December 2008

SUMMARY
A radioimmunoassay has been developed for plasma arginine-vasopressin in man and dog. The mean recovery of added arginine-vasopressin (AVP) was 60 ± 6·9 (s.d.)% and the lower threshold of detection 2·0 pmol/l. A close correlation was found between concurrent radioimmunoassay and bioassay values. The mean concentration found in peripheral venous blood in healthy men after overnight fasting was 5·3 pmol/l (range 4·6–6·2 pmol/l). In man, significant increases in plasma AVP occurred after dehydration (5·9–9·5 pmol/l) and significant decreases after oral water-loading (5·2–3·7 pmol/l). During i.v. infusion of graded doses of synthetic AVP in normal men, plasma levels were closely correlated with infusion rate. On stopping the infusion, plasma vasopressin fell exponentially with a half-life of between 7 and 8 min. In man, plasma AVP was unaffected by tilting head-up for 2 h, or by a non-hypotensive bleeding of 500 ml in 10 min. In the dog, haemorrhage of 5 ml/kg and over caused proportionate increases in AVP in the circulation. In normal men, plasma vasopressin was significantly correlated with concurrent urinary osmolality. Five patients with oat-cell bronchial carcinoma and hyponatraemia showed a marked increase of plasma vasopressin. Five patients with diabetes insipidus had significantly reduced, but detectable, levels of plasma AVP. The plasma concentration in these patients did not increase after water restriction.
INHIBITORY EFFECT OF PROGESTERONE ON THE LACTOGENIC AND ABORTIVE ACTION OF PROSTAGLANDIN F2α
Authors: VERMOUTH NELIA T. , DEIS R. P. 
Published: December 2008

SUMMARY
The effect of ovariectomy, progesterone and prolactin treatment on the action of prostaglandin F2α (PGF2α) was determined in pregnant rats. PGF2α (150 μg × 2) injected i.p. on day 19 or 18 of pregnancy induced lactogenesis about 25 h later and abortion on days 20 and 21 of pregnancy. Treatment with PGF2α (100 μg × 2 or 50 μg × 2) on day 19 induced lactogenesis around 22 or 38 h later, respectively, and abortion on day 21. PGF2α treatment on day 17 was less effective. Unilateral ovariectomy on day 17 of pregnancy induced lactogenesis 32 h later but not abortion. PGF2α (150 μg × 2) given on the day of surgery advanced lactogenesis 12 h and rats aborted on day 19. Bilateral ovariectomy on day 17 induced abortion between days 20 to 21, but if a single dose of PGF2α (300 μg) was injected on day 18, all the ovariectomized rats aborted on day 19. Progesterone (10 mg) injected into rats treated with PGF2α (150 μg × 2) on day 18, prevented abortion and delayed lactogenesis. Prolactin (1 mg × 4) treatment delayed only abortion. Serum prolactin levels were significantly higher 12 h after the last dose of PGF2α (150 μg × 2) in rats treated on days 17, 18 or 19 of pregnancy. Pretreatment with progesterone prevented the rise in prolactin concentration. These results suggest that the lactogenic and abortive action of PGF2α may be dependent on the uterine and plasma concentration of progesterone.
CALCITONIN PRODUCTION BY RAT THYROID TUMOURS
Authors: TRIGGS S. M. , HESCH R. D. , WOODHEAD J. S. , WILLIAMS E. D. 
Published: December 2008

SUMMARY
Immunolocalization techniques have been used to study 16 rat thyroids containing C cell tumours and ten rat thyroids in which no tumours or hyperplasias were found. All rats in these groups were at least 2 years old. An indirect ('sandwich') technique was used which involved rabbit or goat anti-human calcitonin antiserum and either fluorescein or peroxidase-labelled anti-rabbit or anti-goat IgG.
Plasma calcitonin levels were measured in these animals and in a further group of ten young normal rats by means of an immunoradiometric assay using goat antiserum against synthetic human calcitonin.
Both normal C cells and C cell tumours showed either apple-green fluorescence or positive peroxidase staining. The intensity of staining in the tumours varied from one cell to another but was in general less than that found for normal C cells. Calcitonin in the blood was detectable in most animals. The mean concentration found in young normal animals was 265 pg/ml (range < 100–600 pg/ml), in old normal animals 160 pg/ml (range < 100– 400 pg/ml) and in rats with small C cell tumours 470 pg/ml (range 100–1200 pg/ml). The mean concentration in this latter group differed significantly from those of both normal groups (P < 0·05). One animal with an invasive C cell tumour had a greatly increased calcitonin concentration (> 5 ng/ml) in the circulation.
The results showed that calcitonin was present in normal rat C cells and that C cell tumours both contained and secreted calcitonin, underlining the similarity between these tumours and human medullary carcinomata.