bluuebunny/crossref_metadata_2025_split huggingface dataset:
RESPONSE OF MOUSE GRAAFIAN FOLLICLES IN ORGAN CULTURE TO VARYING DOSES OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE
Authors: NEAL P. , BAKER T. G. 
Published: December 2008

SUMMARY
The response of mouse ovaries maintained in organ culture to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) was assessed using quantitative histological and radioimmunoassay techniques.
In terms of the induction of preovulatory maturation in follicular oocytes, 1 μg FSH/ml medium was as effective as 10 μg LH/ml. The lowest doses of HCG and LH used (0·2 i.u./ml and 1 μg/ml respectively) had no effect on oocyte maturation, whereas the response to FSH was virtually unchanged irrespective of dose (1–10 μg/ml). When the level of progesterone in the medium at the end of organ culture was used as an index of ovarian response, LH was more effective than FSH and HCG, although all the hormones induced a significant increase, irrespective of dose.
These results are discussed in terms of the mode of action of gonadotrophins in the processes culminating in ovulation.
EFFECT OF PROSTAGLANDIN E2 AND A2 ON STEROID SYNTHESIS BY THE RAT ADRENAL GLAND
Authors: SPÄT A. , JÓZAN SARA 
Published: December 2008

SUMMARY
Prostaglandin E2 increased aldosterone output by superfused capsular adrenal glands obtained from sodium-repleted, hypophysectomized rats but corticosterone did not show a statistically significant increase. Prostaglandin A2 increased corticosterone but not aldosterone production by incubated capsular glands obtained from sodium-repleted, hypophysectomized rats. Both aldosterone and corticosterone production rates were increased by PGA2 after previous sodium restriction. Corticosterone production rate of the decapsulated adrenal gland was not significantly modified by prostaglandin A2 in a concentration effective on the capsular adrenal gland. A possible role of prostaglandins in the regulation of aldosterone secretion is discussed.
STUDIES ON THE NATURE OF MAMMALIAN HYPOTHALAMIC THYROTROPHIN RELEASING HORMONE USING IMMUNOCHEMICAL, CHROMATOGRAPHIC AND ENZYMIC TECHNIQUES
Authors: JEFFCOATE S. L. , WHITE N. 
Published: December 2008

SUMMARY
Hypothalamic extracts from three mammalian species (rat, rabbit and sheep) were found to contain several ng of immunoreactive thyrotrophin releasing hormone (TRH)-like activity. This substance chromatographed on ion exchange chromatography (carboxymethyl cellulose) as a single peak that was indistinguishable from synthetic TRH. Hypothalamic TRH was also inactivated by normal human plasma at a rate (1·21–1·46%/μl plasma/h and 1·59–1·77%/50 μl plasma/min) similar to that of synthetic TRH (1·42%/μl plasma/h and 1·73%/50 μl plasma/min). This combination of chromatographic and enzymic techniques can be applied to the identification of immunoreactive TRH in body fluids.
AROMATIZING ACTIVITY OF PLACENTAL MICROSOMAL FRACTIONS FROM EWES IN LATE GESTATION
Authors: MANN M. R. , CURET L. B. , COLAS A. E. 
Published: December 2008

SUMMARY
Placental microsomes from eight domestic sheep at 136–146 days of gestation were incubated with radioactive androstenedione, testosterone and dehydroepiandrosterone. Aromatizing activity was examined in the presence and absence of cortisol and the rates of both oestrone and oestradiol synthesis were measured. Oestrone predominated in preference to oestradiol in most of the incubations, a result opposite to that found with human placentae. The sharp increase in the rate of oestradiol production found in the 144- to 146-day-old placentae incubated with testosterone may indicate a more rapid increase of aromatizing than of 17β-hydroxysteroid dehydrogenase activity. The presence of cortisol in the mixtures did not significantly affect the placental aromatizing activity, indicating that there is no direct effect of cortisol on the enzyme system as measured in vitro.
The dramatic rise of overall mean aromatizing activity from 4·86 ± 0·22 (s.e.m.) at 138–141 days of gestation to 12·96 ± 0·38 pmol/mg protein/min at 144–146 days (with a greater relative increase in the rate of oestradiol formation), suggests that changes in placental aromatizing activity may play an important role in maternal and foetal plasma oestrogen surges before ovine parturition.
RAPID PURIFICATION OF TRI-IODOTHYRONINE AND THYROXINE PROTEIN CONJUGATES FOR ANTIBODY PRODUCTION
Authors: BURKE C. W. , SHAKESPEAR R. A. 
Published: December 2008

SUMMARY
Thyroxine (T4) and tri-iodothyronine (T3) were coupled to human serum albumin (HSA) with carbodi-imide. By adsorption chromatography on Sephadex G-25, fractions containing purified conjugate, but not reversibly-bound T3 or T4, were obtained, and this procedure took 5 h; considerably less than the conventional dialysis technique. Highly specific high-titre antisera were produced in rabbits and guinea-pigs by injection of these fractions in Freund's adjuvant.
SUPPRESSION OF PROGESTERONE SECRETION IN LACTATING RATS BY ADMINISTRATION OF ERGOCORNINE AND THE EFFECT OF PROLACTIN REPLACEMENT
Authors: TOMOGANE H. , ÔTA K. , YOKOYAMA A. 
Published: December 2008

SUMMARY
In order to assess the stimulatory effect of prolactin on the secretion of progesterone from corpora lutea in lactating rats, ergocornine maleate (ECO; 1 mg/day), an inhibitor of prolactin secretion, was administered subcutaneously on days 6 and 7 of lactation in primiparous rats. By day 8 of lactation, the concentration of progesterone in ovarian venous blood fell to an undetectable level in the ECO-treated animals, while the concentration in the control animals was very high at this stage of lactation. The level of 20α-hydroxypregn-4-en3-one was significantly higher on day 8 of lactation in ECO-treated than in control rats. Lactational dioestrus was interrupted by treatment with ECO and vaginal oestrus appeared 3–4 days after the start of treatment. Administration of ECO caused deleterious depression of milk production and of food intake of mother rats. In the pair-fed control animals, lactation continued almost normally throughout the experimental period. Prolactin (1 mg/day) administered simultaneously with ECO increased progesterone to levels even higher than those in control rats and restored 20α-hydroxypregn-4-en-3-one levels to those of the controls. The effect of the drug on milk production was alleviated.
The results strongly suggest that prolactin is the most important factor in maintaining the function of corpora lutea in the lactating rat.
DYNAMICS OF INSULIN RELEASE BY PERFUSED HAMSTER (MESOCRICETUS AURATUS) PANCREASES: EFFECTS OF HYPOPHYSECTOMY, BOVINE AND HUMAN GROWTH HORMONE, AND PROLACTIN
Authors: CURRYt DONALD L. , BENNETT LESLIE L. , LI CHOH HAO 
Published: December 2008

SUMMARY
The hamster exhibits a biphasic pattern of insulin secretion; however, the dynamic response differs qualitatively from that of the rat in that there is a steady-state second release phase. A marked attenuation of insulin secretion as a result of hypophysectomy was observed after 3 weeks, but not after 2 weeks. This depression of insulin secretion was restored to near or above normal levels by bovine growth hormone, human growth hormone, and prolactin.
THE THYROXINE-BINDING PROPERTIES OF SERUM PROTEINS. A COMPETITIVE BINDING TECHNIQUE EMPLOYING SEPHADEX G-25
Authors: SUTHERLAND R. L. , SIMPSON-MORGAN M. W. 
Published: December 2008

SUMMARY
A competitive binding technique is described for the estimation of the thyroxine (T4)-binding properties of serum proteins in dilute blood serum and lymph. When used in conjunction with an assay for total T4 the following parameters can be estimated: the number of functionally different T4 binding proteins, their individual association constants and binding capacities for T4, the amount of T4 which is bound to each binding species, and the concentration of unbound (free) T4.
Both human and sheep serum have three functionally different T4-binding proteins. The association constants for the three human proteins were 9·5 × 109, 1·6 × 108 and 3·1 × 105 1/mol for T4-binding globulin (TBG), T4-binding prealbumin (TBPA) and serum albumin, respectively. The corresponding sheep proteins, TBG, TBP-2 and albumin, had association constants of 8·9 × 109, 1·4 × 108 and 3·5 × 1051/mol. Human TBG had a mean binding capacity of 21·3 μg/100 ml and that of ovine TBG was 12·8 μg/100 ml. The other specific binding proteins (TBPA in man and TBP-2 in sheep) had mean binding capacities of 307 and 359 μg/100 ml respectively.
Two functionally different T4-binding proteins were identified in rat serum.
EFFECTS OF ANTIBODY TO OESTROGEN OR OF OVARIECTOMY ON THE INCORPORATION OF [35S]METHIONINE INTO BRAIN PROTEIN AND ON GONADOTROPHIN LEVELS DURING THE OESTROUS CYCLE IN THE RAT
Authors: TER HAAR M. B. , MACKINNON P. C. B. 
Published: December 2008

SUMMARY
The incorporation of [35S]methionine into protein of the anterior pituitary and discrete brain areas was measured following the administration of antibodies to oestrogen, ovariectomy, or adrenalectomy on the afternoon of dioestrus. The antibody to oestrogen deleted the circadian rhythms of methionine incorporation normally observed in the various brain areas together with the peaks of incorporation normally observed in the median eminence area and anterior pituitary on the evening of pro-oestrus. The peaks of incorporative activity normally observed in the preoptic area and amygdala (relative to the putamen) at 03.00 h on the day of pro-oestrus were also deleted. Administration of the antiserum on the morning of pro-oestrus failed to alter the pattern of methionine incorporation normally observed on the evening of pro-oestrus.
Ovariectomy performed at 16.00 h of dioestrus blocked the preovulatory rise of luteinizing hormone (LH) (as did the antibody to oestrogen) and inhibited the peak of methionine incorporation normally observed in the anterior pituitary on the evening of pro-oestrus. However, for the peak in the median eminence to be inhibited, ovariectomy had to be performed on the morning of the preceding oestrus. Adrenalectomy alone, or adrenalectomy with ovariectomy, performed on the afternoon of dioestrus did not affect the levels of methionine incorporation in the brain or anterior pituitary at 18.00 h on the day of prooestrus.
Animals which had been ovariectomized and injected with 2·5 μg oestradiol benzoate on the morning of oestrus showed significantly increased levels of methionine incorporation in all the brain areas and the anterior pituitary at 18.00 h of expected pro-oestrus. The administration of antibody to oestrogen to a similar group of animals on the afternoon of expected dioestrus inhibited the rise at 18.00 h of expected pro-oestrus. The apparent discrepancy between the results obtained with ovariectomy and the antiserum appeared to be due to the ability of the antiserum to neutralize the activity of oestrogens retained by the tissues.
The present results suggest that the changes in incorporation of methionine into protein in the brain and anterior pituitary are brought about by the action of endogenous oestrogen: there appears to be a steady summative effect on the median eminence throughout the oestrous cycle together with a short-lived effect occurring during pro-oestrus and affecting the anterior pituitary.
THE RESPONSIVENESS OF THE ANTERIOR PITUITARY GLAND TO LUTEINIZING HORMONE RELEASING FACTOR IN RATS EXPOSED TO CONSTANT LIGHT
Authors: FINK G. 
Published: December 2008

SUMMARY
The responsiveness of the anterior pituitary gland to synthetic luteinizing hormone releasing factor (LH-RF) was tested in rats exposed to constant light. At a dosage of 50 ng LH-RF/ 100 g body wt the mean maximal increments in plasma LH and FSH were similar to those at 10.00 h of pro-oestrus. The increments in the plasma gonadotrophins at dosages of 500 and 1000 ng LH-RF/100 g body wt did not differ significantly from those at 250 ng LH-RF/ 100 g body wt. These findings suggest that, in contrast to rats which exhibit regular oestrous cycles, the preovulatory (post-coital) release of LH in rats exposed to constant light may depend almost entirely on the release of a relatively large amount of LH-RF into hypophysial portal vessel blood. Whereas in pro-oestrous animals a relatively small fraction of the readily releasable pool of LH is released during the spontaneous preovulatory surge, in rats exposed to constant light most releasable LH appears to be discharged during the reflex preovulatory surge of this hormone. The concentrations of radioimmunoassayable FSH in blood samples withdrawn before the injection of LH-RF support the view that FSH secretion in the rat is increased by constant exposure to light.
EFFECT OF INTRAVENOUS AND INTRACAROTID INJECTIONS OF HYPERTONIC FLUIDS ON THE RELEASE OF MELANOCYTE-STIMULATING HORMONE FROM THE RAT POSTERIOR PITUITARY LOBE INCUBATED IN SITU
Authors: CYRKOWICZ A. , TRACZYK W. Z. 
Published: December 2008

SUMMARY
The posterior pituitary lobe of male rats under urethane anaesthesia was incubated in situ. The pituitary gland was exposed by the transpharyngeal approach. The posterior lobe remained in neural and partial vascular connexion with the hypothalamus, whereas the anterior lobe was entirely removed. Incubation fluid was collected and its melanophore-stimulating activity was assayed in hypophysectomized frogs. No effect was observed after the i.v. injection of 1 ml 120 μm-NaCl with 60 μm-CaCl2 or isotonic NaCl solution.
Hypertonic solutions of 5% NaCl and 25% glucose injected intravenously to the limit of 0·5% of the body weight, transiently enhanced the release of MSH from the posterior pituitary lobe by 66% (significant) and 15% (not significant) respectively. Intracarotid injection of 0·3 ml 5% NaCl solution resulted in the highest increase (95%) of MSH release.
LOCALIZATION OF PROLACTIN IN RAT KIDNEY TISSUE USING A DOUBLE-ANTIBODY TECHNIQUE
Authors: DONATSCH P. , RICHARDSON B. 
Published: December 2008

SUMMARY
A fluorescein-labelled double-antibody technique was used for the microscopical localization of ovine prolactin in kidney tissue of rats previously injected intravenously with 50 i.u. of the hormone at varying intervals before death.
Thirty seconds after the injection, the hormone could already be visualized in the lumina of the proximal tubules. After 2 min, discrete particulate fluorescence appeared on the brush border of the epithelium of the proximal tubules. Three minutes later prolactin was clearly localized in the apical portion of the cytoplasm of these cells as well as on the brush border. Ten minutes after the injection, the hormone appeared exclusively within the cell, highest concentrations being observed in the perinuclear region. After 20 min, however, the hormone appeared evenly distributed throughout the cytoplasm. The distribution of prolactin was in all cases confined to the proximal tubular region of the nephron.
The findings support the suggestion that the site of action of prolactin in the kidney is the epithelium of the proximal tubule. As prolactin was first visualized in the lumen of this portion of the nephron, it appears that the hormone gains access to these cells via the glomerular filtrate.
INFLUENCE OF SERUM FREE FATTY ACID LEVELS ON GROWTH HORMONE SECRETION IN LACTATING COWS
Authors: REYNAERT R. , DE PAEPE M. , MARCUS S. , PEETERS G. 
Published: December 2008

SUMMARY
The influence of intravenous injections or infusions of insulin (0·2 i.u./kg), propranolol (150 mg), 3,5-dimethylpyrazole (3 mg/kg), 3,5-dimethylisoxazole (0·08 mg/kg), glucose (0·5 g/kg), nicotinic acid (120 mg/kg), arginine (0·5 g/kg) or butyrate (0·5 mmol/kg) on plasma glucose levels, and on serum concentrations of growth hormone and free fatty acids of lactating cows was investigated. In all of these experiments we noted an increase in the level of growth hormone. This increase was not a direct consequence of alterations in the glucose concentration, since the growth hormone peak occurred both during a decrease (insulin, 3,5-dimethylisoxazole, nicotinic acid and butyrate tests), and during an increase of the glucose level (glucose, arginine and propranolol tests), whereas the glucose concentration remained unchanged during the 3,5-dimethylpyrazole experiments. However, in each instance a precipitous fall of the free fatty acid level was noted.
The glucose, growth hormone, and free fatty acid levels of lactating cows were not affected by either i.v. injection or infusion of saline.
METABOLIC CLEARANCE RATE, PRODUCTION RATE, AND MAMMARY UPTAKE AND METABOLISM OF PROGESTERONE IN COWS
Authors: HEAP R. B. , HENVILLE A. , LINZELL J. L. 
Published: December 2008

SUMMARY
Tracer kinetic techniques have been used to measure the production rate, metabolic clearance rate and mammary uptake of progesterone in six experiments on two Jersey cows. The cows were surgically prepared so that the carotid artery, jugular vein and mammary vein concentrations of progesterone, and udder blood flow, could be determined in conscious animals without anaesthesia or stress.
The mean production rate of progesterone was 173 ± 23·3 (s.e.m.) μg/min, with values ranging from 80 to 276 μg/min in pregnancy. The metabolic clearance rate was 22·5 ± 2·0 1/min, or 0·21 ± 0·025 1/min/kg metabolic body weight. The mammary uptake of progesterone was low, 3·1 ± 1·1 μg/min, and udder uptake accounted for about 3% of progesterone production rate.
During [3H]progesterone infusion, radioactivity was transferred from blood to milk, probably by diffusion down a concentration gradient. Progesterone accounted for more than 88% of the ether-soluble radioactivity recovered from milk.
EFFECT OF PROGESTERONE ON COLLAGEN BREAKDOWN AND TISSUE COLLAGENOLYTIC ACTIVITY IN THE INVOLUTING RAT UTERUS
Authors: HALME JOUKO , WOESSNER J. F. 
Published: December 2008

SUMMARY
Progestational agents were studied for their effects on collagenolytic activity and loss of collagen and wet weight from the involuting post-partum rat uterus. Administration of very large doses of progesterone (80–150 mg/day) significantly retarded uterine involution and loss of collagen. This was accompanied by a significant reduction in uterine collagenolytic activity. By 72 h post partum, uteri of rats treated with 150 mg progesterone/day had wet weights 30% above, collagen 85% above, and collagenolytic activity 45% below, those of the control uteri.
Similar effects were produced by 17α-acetoxy-6α-methylprogesterone at the same dosage levels. However, the progestational agent 6α-chloro-17α-acetoxypregna-4,6-diene-3,20dione acetate had no effect in this system.
EFFECT OF INTRAVENTRICULAR ADMINISTRATION OF NORADRENALINE ON WATER DIURESIS IN GOATS
Authors: MESSOM G. VANDEPUTTE-VAN , PEETERS G. 
Published: December 2008

SUMMARY
During water diuresis in conscious goats, noradrenaline (NA), its antagonists phentolamine, phenoxybenzamine and propranolol and also atropine were administered into the 3rd ventricle. The subsequent effects on water diuresis and on the excretion rates of Na+, K+ and Cl− were investigated.
Infusion of NA into the 3rd ventricle induced a strong and significant antidiuretic response and a decrease in the Na+: K+ excretion ratio; these effects were dose-dependent. High doses of NA produced a significant increase in urinary K+ excretion. Similar results were observed after i.v. administration of arginine-vasopressin.
Pretreatment with phentolamine injected into the 3rd ventricle produced a dose-dependent inhibition of the NA-induced antidiuretic effects. Phenoxybenzamine also blocked the response to NA but a dose-response relationship was not apparent. Atropine and propranolol did not block the response to NA.
RELATIONSHIP BETWEEN THE ENDOCRINE ENVIRONMENT WITHIN THE GRAAFIAN FOLLICLE AND THE SUBSEQUENT RATE OF PROGESTERONE SECRETION BY HUMAN GRANULOSA CELLS IN VITRO
Authors: McNATTY K. P. , SAWERS R. S. 
Published: December 2008

SUMMARY
The steroidogenic potential of granulosa cells harvested from human Graafian follicles containing varying concentrations of pituitary and steroid hormones was examined. The mitotic activity and production of progesterone by granulosa cells in vitro was found to be correlated with their hormonal environment at the time of harvesting. Only cells from follicles containing some FSH and high concentrations of oestradiol underwent spontaneous mitosis in vitro. However, mitosis could be induced by adding FSH and high concentrations of oestradiol to the culture, provided that the concentration of LH was low. Cells harvested from follicles containing LH, FSH and high concentrations of oestradiol secreted significantly more progesterone than cells from follicles which did not contain all three hormones.
It is suggested that after the initiation of follicular development by FSH, a long period of exposure (8–10 days) to both FSH and oestradiol is necessary before the maximum biosynthetic capacity of granulosa cells is achieved; this synthetic potential is then only realized under the influence of LH and prolactin. Premature exposure to LH inhibits both the mitotic activity and the steroidogenic potential of these cells.
CHANGES IN PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AFTER INJECTION OF PROGESTERONE AT VARIOUS TIMES DURING THE OVULATORY CYCLE OF THE DOMESTIC HEN (GALLUS DOMESTICUS)
Authors: WILSON SUSAN C. , SHARP P. J. 
Published: December 2008

SUMMARY
Changes in plasma LH concentrations after i.m. injections of 0·5 mg progesterone/kg at various stages of the ovulatory cycle were measured by radioimmunoassay. Four types of response were observed. (1) When the steroid was injected between 4 h after and 12 h before an ovulation, LH levels started to rise after 15–45 min and reached peak values within 90–120 min. The mean maximal incremental change in the level of LH was 1·58 ± 0·10 (s.e.m.) ng/ml (n = 37). (2) In contrast, when progesterone was injected 12–8 h before ovulation, i.e. immediately before a spontaneous pre-ovulatory LH surge, the resulting mean maximal incremental change in LH level, 0·79 ± 0·12 ng/ml (n = 9), was significantly smaller (P < 0·001). (3) If progesterone was injected 8–4 h before ovulation, i.e. when pre-ovulatory LH levels were rising, they immediately started to rise more rapidly and reached peak values within 45 min. The maximal incremental change in the level of LH under these circumstances, 2·34 ± 0·20 ng/ml (n = 12), was significantly greater (P < 0·001 in both cases) than the changes observed in the responses 1 and 2 described above. (4) Levels of LH generally showed no incremental change in response to injections of progesterone given 4–0 h before ovulation, i.e. when pre-ovulatory LH levels were falling.
It was concluded that the type of change in plasma LH levels induced by progesterone depended upon the stage of the ovulatory cycle at which the steroid was injected.
DEHYDROEPIANDROSTERONE-INDUCED THYROTROPHIN RELEASE DURING HEAT STRESS IN RATS
Authors: TAL E. , SULMAN F. G. 
Published: December 2008

SUMMARY
Six groups each of 12 male albino rats were reared from day 21 of life at temperatures of 23, 34 or 37 °C. While the rats survived for unlimited periods at 23 and 34 °C, the animals reared at 37 °C succumbed within 5 days to heat stress. The latter group, when injected s.c. or i.p. with 50 mg dehydroepiandrosterone (DHA)/kg/day were no longer affected by the heat. During this treatment thyroid epithelial cell height doubled, colloid decreased by 20%, connective tissue did not change, the basic metabolic rate decreased by 10% and rectal temperatures of the treated rats increased with the ambient temperatures. Body weight increased only slightly, pituitary TSH decreased by 25%, serum TSH increased by over 50%, thyroxine and 125I uptake increased by 200%. The survival of the DHA-treated rats was apparently secured by blocking the hypothalamic thermoreceptors.