bluuebunny/crossref_metadata_2025_split huggingface dataset:
RENAL DIURESIS AFTER INJECTIONS OF THE FRESHWATER EEL AND ANTIDIURESIS ARGININE VASOTOCIN IN (ANGUILLA ANGUILLA L.)
Authors: HENDERSON I. W. , WALES N. A. M. 
Published: December 2008

SUMMARY
The renal responses of the freshwater-adapted eel, Anguilla anguilla L. to arginine vasotocin ([8-arginine]-oxytocin) have been examined. The quality of the responses to the intravenously administered peptide was found to vary with the dose. Less than 0·1 ng/kg body weight reduced glomerular filtration rate, free water clearance and rate of urine production for up to 60 min. Doses greater than 1·0 ng/kg body weight induced a 'glomerular diuresis', i.e. increased rates of urine production, glomerular filtration and free water clearance for 40–60 min. Neither the diuretic nor the antidiuretic doses produce changes in urinary composition, and no obvious direct tubular actions of the peptide were found. Arterial blood pressure, measured in the dorsal aorta, increased with some of the diuretic doses, whilst the lower doses (less than 10 ng/kg body weight) had little or no cardiovascular actions. The mechanisms involved in these dose—response characteristics are discussed with particular regard to the renal function of lower vertebrates. It is suggested that arginine vasotocin plays a primary or secondary role in the modulation of 'glomerular intermittency'.
EFFECTS OF FRESHWATER ADAPTATION AND OF PROLACTIN ON SODIUM-POTASSIUMACTIVATED ADENOSINE TRIPHOSPHATASE ACTIVITY IN THE URINARY BLADDER OF TWO FLOUNDER SPECIES
Authors: UTIDA S. , KAMIYA MIE , JOHNSON D. W. , BERN H. A. 
Published: December 2008

SUMMARY
Sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase) activity increased in the urinary bladder of the euryhaline teleost Platichthys stellatus after transfer from sea-water to fresh water. This increase also occurred after injection of prolactin into seawater Platichthys, simulating the results of freshwater transfer. In Kareius bicoloratus, which does not survive transfer to fresh water, prolactin does not increase bladder Na-K-ATPase activity. The differences in response of these two species to prolactin may be related to the degree of their euryhalinity. There may be a relationship between adaptability to fresh water and responsiveness of bladder Na-K-ATPase to prolactin.
IMMUNOCHEMICAL AND CHROMATOGRAPHIC SIMILARITY OF RAT, RABBIT, CHICKEN AND SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONES
Authors: JEFFCOATE S. L. , SHARP P. J. , FRASER H. M. , HOLLAND D. T. , GUNN A. 
Published: December 2008

SUMMARY
Luteinizing hormone releasing hormone (LH-RH) was detected in hypothalamic extracts of rats, rabbits and chickens using a radioimmunoassay for synthetic LH-RH decapeptide. The mobilities of the immunologically active fraction and of synthetic LH-RH were the same in various chromatographic systems (gel filtration on Sephadex, thin-layer chromatography on silica gel and ion-exchange chromatography on carboxymethylcellulose) suggesting that mammalian, avian and synthetic LH-RH's are closely related.
EFFECT OF PERINATAL HYPOTHYROIDISM ON PITUITARY SECRETION OF GROWTH HORMONE AND PROLACTIN IN RATS
Authors: KIKUYAMA SAKAE , NAGASAWA HIROSHI , YANAI REIKO , YAMANOUCHI KOREHITO 
Published: December 2008

SUMMARY
Female Sprague—Dawley rats were fed 6-propyl-2-thiouracil (PTU) in their diet during late pregnancy and lactation. The growth and gonadal development of their pups were inhibited and in females the day of vaginal opening and onset of oestrous cycles were delayed; thyroid glands were hypertrophied. Treatment of the pups with thyroxine largely reversed these changes. The effect on body weight persisted even after treatment with PTU had stopped. At 20 days of age, the anterior pituitary glands of the pups of PTU-treated mothers contained significantly less growth hormone (GH) and prolactin than those of normal pups of both sexes. These changes persisted at 60 days of age. If the pups of PTU-treated mothers were given thyroxine from day 1 to day 20 of age, pituitary GH and prolactin content on day 20 had returned towards normal values. Thyroid deficiency was found to suppress the synthesis and release of prolactin and the synthesis of GH by the pituitary in vitro.
These findings suggest that thyroxine influenced the maturation of the pituitary directly and/or through the hypothalamus and that thyroxine deficiency in early life brought about persistent alteration of the pituitary secretion of GH and prolactin.
INFLUENCE OF PROLONGED GLUCOSE INFUSIONS ON PLASMA INSULIN AND GROWTH HORMONE CONCENTRATIONS OF FOETAL LAMBS
Authors: BASSETT J. M. , MADILL DENISE 
Published: December 2008

SUMMARY
Chronically cannulated foetal lambs close to term were infused intravenously with glucose at rates of 40 or 70 mg/min for up to 5 days. Infusion at these rates increased the foetal plasma glucose concentration to values in the ranges 35–45 and 60–80 mg/100 ml respectively. There were related increases in plasma fructose and lactate concentrations.
Foetal plasma insulin concentrations increased within the first hour and remained raised throughout infusion. Plasma insulin concentrations were significantly correlated with plasma glucose concentrations. The secretory response of insulin to subsequent glucose infusions at a rate of 140 mg/min was not increased by the previous prolonged glucose infusions.
Glucose infusion resulted in decreased plasma growth hormone concentrations in three of the lambs infused, but over the total number of observations plasma glucose and growth hormone concentrations were not significantly correlated.
THE HORMONAL MECHANISM OF IMMUNOPOTENTIATION IN MICE AFTER ORCHIDECTOMY
Authors: CASTRO J. E. 
Published: December 2008

SUMMARY
Orchidectomy of Balb C mice aged between 4 and 6 weeks delayed the normal rate of thymic involution. Testosterone replacement after orchidectomy prevented this relative thymic enlargement and testosterone supplements given to intact mice accelerated the normal rate of thymic involution.
When hypopituitary, dwarf mice were given somatotrophin and thyroxine alone there was no significant difference in the thymic weights of control or orchidectomized mice. When replacement therapy included gonadotrophin, orchidectomy was associated with significant thymic hypertrophy. Passive transfer of serum from previously orchidectomized mice did not change the thymic weight of normal recipient mice.
These experiments suggest that testosterone exerts a constant moderating effect on the thymus and the immunological effects of orchidectomy are due to the direct effects of androgen withdrawal.
EFFECTS OF NADPH, NADP+, SUCCINATE AND CYCLIC AMP ON PROGESTERONE SYNTHESIS IN SUBCELLULAR FRACTIONS OF RABBIT OVARIAN INTERSTITIAL TISSUE
Authors: SCOON V. , MAJOR PATRICIA W. 
Published: December 2008

SUMMARY
The effects of NADPH, NADP+, succinate and cyclic AMP on progestational steroid synthesis have been investigated in subcellular fractions of rabbit interstitial tissue. Production of progesterone and 20α-hydroxy-4-pregnen-3-one increased during incubation of mitochondria with NADPH and NADP+ respectively, and an increase in 20α-hydroxy-4-pregnen-3-one was observed after incubation of microsomes with NADP+. No changes in progestational steroid production were observed in individual cell fractions after incubation with cyclic AMP or succinate. However, a small but significant increase in progesterone synthesis occurred in a combined fraction containing mitochondria, microsomes and cytosol when incubated with cyclic AMP.
SHORT-TERM EFFECTS OF OESTRADIOL BENZOATE IN NORMAL, HYPOPHYSECTOMIZED AND ALLOXAN-DIABETIC MALE RATS
Authors: GOODMAN M. N. , HAZELWOOD R. L. 
Published: December 2008

SUMMARY
Studies were undertaken to determine the effects and possible mode of action of 17β-oestradiol benzoate (OEB) in alloxan-diabetic male rats. Adlibitum or pair-fed normal, diabetic, and hypophysectomized rats received daily subcutaneous injections of 10 μg OEB for 10 days. In normal rats, OEB decreased plasma glucose, increased plasma immunoreactive insulin, growth hormone and corticosteroid levels, increased pancreatic β-cell granulation, and enhanced glucose stimulation of insulin release in vitro. In alloxan-diabetic rats, OEB treatment decreased urinary glucose excretion, increased plasma growth hormone and corticosteroid levels and slightly enlarged the pancreatic islets of Langerhans. In hypophysectomized rats, OEB decreased plasma glucose, increased plasma insulin levels, and slightly enlarged the pancreatic islets of Langerhans.
These results suggest that OEB affects experimental diabetes by a direct action on the pancreas, promoting insulin formation, and possibly by an indirect action mediated through hypophysial secretions.
EFFECT OF DEXAMETHASONE ON CELL POPULATION KINETICS IN THE ADRENAL CORTEX OF THE PREPUBERTAL MALE RAT
Authors: WRIGHT N. A. , APPLETON D. R. , MORLEY A. R. 
Published: December 2008

SUMMARY
The effect of a single injection of dexamethasone on adrenocortical cell proliferation was studied in prepubertal male rats using tritiated thymidine. After a short latent period, all zones of the adrenal cortex showed a rapid decrease in both labelling and mitotic indices. After a prolonged period when very low indices were apparent, there was a rapid rise in both proliferative indices with most zones showing a considerable increase above control values.
A more detailed study of the initial depression showed that after a latent period of about 5 h the labelling index fell approximately 8 h before the mitotic index. This differential response in the labelling and mitotic indices was consistent with a block in the cell cycle late in the pre-DNA synthetic interval of the cell cycle (G1), with cells being prevented from entering DNA synthesis. This hypothesis was also supported by an experiment involving continuous labelling of control and dexamethasone-treated animals; again after a latent period of 5–6 h, the rate of increase of the continuous labelling index fell as cells became blocked in late G1.
By analogy with other tissues, results are interpreted in terms of a direct action of dexamethasone on adrenocortical cells; this steroid-sensitive step in the cell cycle may be important in the control of growth in the adrenal cortex.
GLUCOSE-INDUCED INCREASE OF PLASMA INSULIN IN THE RAT FOETUS IN UTERO
Authors: KERVRAN A. , GIRARD J. R. 
Published: December 2008

SUMMARY
The effect of glucose on the release of insulin from the pancreas of 18·5 to 21·5-day-old rat foetuses has been studied in utero. Foetal hyperglycaemia was induced by a 1 h glucose infusion into pregnant rats.
In foetuses from mother rats infused with saline, the blood glucose and the plasma insulin concentrations increased up to day 21·5 of gestation. The blood glucose level of the foetuses never exceeded that of the mothers which remained stable from day 18·5 to day 21·5 of gestation.
The infusion of glucose raised the foetal blood glucose concentration to that of the mothers and induced a significant increase of plasma insulin levels both in the mothers and their foetuses. The enhanced plasma insulin concentration observed in the 18·5-day-old foetuses of glucose-infused pregnant rats became greater each day up to 21·5 days.
A PRIMING EFFECT OF LUTEINIZING HORMONE RELEASING FACTOR ON THE ANTERIOR PITUITARY GLAND IN THE FEMALE RAT
Authors: AIYER M. S. , CHIAPPA SHARON A. , FINK G. 
Published: December 2008

SUMMARY
The possibility that luteinizing hormone releasing factor (LH-RF) not only stimulates the secretion of luteinizing hormone (LH) but also has the ability to prime the anterior pituitary gland so that further exposure to LH-RF enhances the responsiveness of the gonadotrophs has been investigated. The effect of two successive i.v. injections of the same dose of LH-RF (50 ng/100 g body weight) on the concentration of LH in plasma was determined in rats anaesthetized with sodium pentobarbitone. Blood samples were collected from the external jugular vein immediately before and at frequent intervals after the injections of LH-RF, and plasma concentrations of LH and, in some samples, follicle-stimulating hormone (FSH) were measured by radioimmunoassay.
In rats anaesthetized with sodium pentobarbitone at 13.30 h of pro-oestrus and injected i.v. with two successive doses of LH-RF, separated by an interval of 30, 60, 120 or 240 min, the LH response to the second injection was significantly greater than that to the first. The LH response was greatest when the two doses were separated by an interval of 60 min. The FSH response to the second injection of LH-RF given 60 min after the first was not significantly different from that to the first injection.
Compared with pro-oestrus, the priming effect of LH-RF was much less at metoestrus and dioestrus, and could not be demonstrated at oestrus. Ovariectomy on the morning of dioestrus reduced the LH responses to the first and second injections of LH-RF given 60 min apart on the afternoon of pro-oestrus, an effect which was partially reversed by administration of oestradiol benzoate shortly after ovariectomy. These findings together with the fact that administration of oestradiol benzoate at metoestrus increased the magnitude of the priming effect of LH-RF at dioestrus suggest that the response at pro-oestrus is dependent upon the rise in plasma oestradiol-17β which reaches a peak on the morning of pro-oestrus.
Although oestrogen plays an important role in determining the magnitude of the priming effect of LH-RF, it appears that none of the steroids secreted by either the ovaries or the adrenal glands mediates this effect since the profile and magnitude of the LH responses to the two doses of LH-RF injected at pro-oestrus into rats adrenalectomized and ovariectomized before the first injection of LH-RF were comparable to those in control animals.
The possible role which the priming effect of LH-RF may play in the development of the preovulatory surge of LH in the rat and man is discussed.
GONADOTROPHIN SECRETION AFTER ELECTRICAL STIMULATION OF THE PREOPTIC AREA DURING THE OESTROUS CYCLE OF THE RAT
Authors: FINK G. , AIYER M. S. 
Published: December 2008

SUMMARY
The responsiveness of the hypothalamo-hypophysial axis to electrical stimulation of the medial preoptic area was tested at various times during the oestrous cycle of the rat. Animals were anaesthetized with sodium pentobarbitone, and glass-insulated bipolar platinum electrodes were stereotaxically implanted in the medial preoptic area. The stimulus consisted of accurately balanced biphasic rectangular pulses, height 500 μA, duration 2 ms and frequency 60 Hz, applied in trains of 30 s intervals. The concentration of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in blood samples withdrawn from the external jugular vein immediately before and at frequent intervals up to 1 h after application of the stimulus was determined by radioimmunoassay. In all animals the stimulus was applied for a period of 15 min, for it was found that under these conditions the profiles of LH and FSH produced in individual animals were similar to those which followed the i.v. injection of 50 ng synthetic luteinizing hormone releasing factor (LH-RF)/100 g body wt, the minimal ovulatory dose of LH-RF in our laboratory.
Both for LH and FSH, the profiles of responsiveness of the hypothalamo-hypophysial axis to electrical stimulation through the oestrous cycle resembled closely the profile of responsiveness of the anterior pituitary gland to LH-RF administered intravenously. There was a relatively gradual increase in pituitary sensitivity, in terms of the mean maximal increments, between the early afternoon of dioestrus and pro-oestrus, followed by an abrupt and marked rise which reached a peak at 18.00 and 21.00 h of pro-oestrus for LH and FSH, respectively. Sensitivity of the hypothalamo-hypophysial axis declined through oestrus and metoestrus reaching a nadir at 13.30 h of dioestrus. While these results do not exclude a change in sensitivity of the neural component of the hypothalamo-hypophysial axis during the oestrus cycle, they do indicate that the timing and magnitude of changes in sensitivity of the anterior pituitary gland to both endogenous and exogenous LH-RF are similar. This raises the possibility that a marked increase in the secretion of LH-RF during the afternoon of pro-oestrus may not be necessary for the occurrence of the surge of LH and FSH, for conceivably the latter could depend on a change in sensitivity of pituitary gonadotrophs to constant or only slightly increased levels of LH-RF in hypophysial portal blood.
Our findings are compared with those of workers who have employed electrochemical stimulation of the preoptic area.
RADIOIMMUNOASSAY OF SYNTHETIC PROGESTOGENS, NORETHISTERONE AND NORGESTREL
Authors: WARREN R. J. , FOTHERBY K. 
Published: December 2008

SUMMARY
Antibodies to norethisterone and norgestrel were raised in rabbits by injecting the steroid 3-carboxymethyloxime coupled to bovine serum albumin. Within 6 months of the first injection, antisera were obtained which gave 50% binding of the labelled steroid at dilutions of 1:100000; after treatment with Rivanol the antisera had titres of 1:20000 to 1:30000. Labelled ligands were prepared by iodination of the tyrosine methyl esters of the steroid oximes; minimum specific activities of 100 to 150 Ci/mmol were obtained. Dextran-charcoal suspension was used for the separation of bound and free labelled steroid. The effect of changes in the incubation conditions on the sensitivity of the assay were investigated. The reliability criteria for the assays were satisfactory, blank values were low and the mean recoveries were greater than 90%. The sensitivity of the method corresponded to a concentration of the steroids in plasma of 30 pg/ml. The coefficient of variation for replicate analyses on the same sample varied from 13·5 to 16%. Apart from the parent steroid, the 3-oxime and the tyrosine methyl ester of the oxime, significant cross-reaction with the antiserum was also obtained with the dihydro and tetrahydro metabolites of the progestogens. After administration orally of 1 mg norgestrel or 1 mg norethisterone to human subjects, peak levels of the steroids in plasma were obtained within 1 to 2 h. Norgestrel was metabolized more slowly than norethisterone. For the periods 2–8 h and 8–24 h after administration of norethisterone the half-lives were approximately 3 h and 5 h respectively; for norgestrel the half-lives were 2·8 h and 10 h. Twenty-four hours after administration, the mean levels of norgestrel and norethisterone in plasma were 1·5 and 0·2 ng/ml respectively corresponding approximately to 0·4% and 0·05% of the dose in the total plasma volume.
INFLUENCE OF THE TROPHOBLAST UPON DIFFERENTIATION OF THE UTERINE EPITHELIUM DURING IMPLANTATION IN THE MOUSE
Authors: POLLARD R. M. , FINN C. A. 
Published: December 2008

SUMMARY
During the preparation of the uterus for implantation of blastocysts the luminal surface of the epithelial cells undergoes a characteristic differentiation. In non-pregnant animals this can be induced by progesterone and oestrogen, but in pregnant animals the basic hormonal control is augmented by a local effect of the blastocyst. This has been demonstrated by examining the uteri of animals made unilaterally pregnant. The differentiation of the luminal epithelial surface of the fertile horn was in advance of that in the sterile horn. The injection of oil into one horn of the uterus of pseudopregnant animals also accelerated the change in the luminal surface of the injected horn.
It is suggested that contact with the cell membrane of the trophoblast influences differentiation of the uterine epithelium and that oil is able to mimic this contact reaction.
SERIAL ASSAYS OF PLASMA GROWTH HORMONE IN TREATED AND UNTREATED ACROMEGALY
Authors: HUNTER W. M. , GILLINGHAM F. J. , HARRIS P. , KANIS J. A. , McGURK F. M. , McLELLAND J. , STRONG J. A. 
Published: December 2008

SUMMARY
Assays for human growth hormone (HGH) were carried out on 89 acromegalic patients, 81 of whom were studied before any treatment had been given. Serial studies were undertaken, generally at 6-monthly intervals, with the same test procedure, using a 50 g oral glucose tolerance test (GTT) and identical assay conditions over a period of 8 years. Twenty-three patients were assessed at intervals during periods of up to 4 years whilst they remained untreated. The general picture was one of unchanging HGH levels.
Ten patients were studied before and after external irradiation. HGH levels showed a slow continuing fall for as long as 4 years and thereafter they stabilized at one-third of pretreatment values. HGH levels in 12 patients treated with radioactive implants showed an immediate fall to one-third, and thereafter a further slow decline to one-tenth of pretreatment levels. The response in eight patients treated by surgical removal of pituitary tissue and subsequent radiotherapy varied considerably.
No patient, treated or untreated, showed evidence of partial suppression of HGH secretion during the GTT although three patients consistently responded to glucose with paradoxical hypersecretion.
EFFECT OF ERGOCORNINE ON PERPHENAZINE-AND OESTROGEN-INDUCED PROLACTIN RELEASE
Authors: KULKARNI P. N. , SIMPSON A. A. 
Published: December 2008

SUMMARY
Both oestradiol and perphenazine induced a significant increase in prolactin release by ovariectomized rats. Ergocornine completely inhibited the initial perphenazine-induced prolactin release which normally reaches a maximum during the first 2·5 h. However, ergocornine did not prevent a significant increase in prolactin release after daily administration of perphenazine. It inhibited oestrogen-induced prolactin release. The results support earlier suggestions that prolactin release is controlled by two mechanisms. Only one of the mechanisms can be blocked by ergocornine.
EFFECTS OF CORTISOL ON THE PRESERVATION OF RAT SKIN AT −3 °C
Authors: DE LOECKER W. , DOMS D. , STAS M. L. 
Published: December 2008

SUMMARY
Although cortisol slightly inhibited the incorporation of 2-14C]glycine into the proteins of rat skin samples incubated in vitro, addition of the hormone to the storage medium had a marked protective effect on protein and DNA metabolism. The incorporation of [2-14C]glycine into the proteins, and to a lesser degree that of [6-3H]thymidine into DNA, were stimulated when the incubated skin had been exposed to cortisol during storage. The skin samples stored in buffer containing cortisol transported α-aminoisobutyric acid more effectively; this was concluded to be due to a stabilizing effect of cortisol on the cell membrane. During storage protein catabolism and possibly protein turnover were stimulated by cortisol.
HORMONAL CONTROL OF PROLIFERATION IN THE GUINEA-PIG UTERUS
Authors: MARCUS G. J. 
Published: December 2008

SUMMARY
In the normal non-pregnant guinea-pig uterus, proliferation of the surface epithelium occurred principally on day 3 after oestrus (vaginal opening). Intense mitotic activity occurred on the following day in the lower regions of the glands. Mitotic activity was pronounced in the endometrial stroma on the succeeding 2 days.
In the ovariectomized guinea-pig, oestrogen stimulated cell devision only in the surface and superficial glandular epithelia, but conditioned the endometrium to respond to progesterone so that at least 2 successive days of progesterone treatment after oestrogen priming elicited both intense glandular proliferation and extensive stromal cell division, while progesterone alone induced uterine closure.
The proliferative responses of the guinea-pig endometrium thus resembled the responses of the rabbit endometrium rather than the rat or mouse endometrial reaction to hormonal stimulation.