bluuebunny/crossref_metadata_2025_split huggingface dataset:
INHIBITION OF MILK SECRETION BY INTRAPERITONEAL INJECTIONS OF MILK INTO LACTATING MICE
Authors: SALA N. L. , CANNATA M. A. , LUTHER E. , ARBALLO J. C. , TRAMEZZANI J. H. 
Published: December 2008

SUMMARY
The effect of milk reabsorption upon lactation was studied by giving daily intraperitoneal injections of milk to lactating mice during the first 5 days of lactation.
The weight gain of the young of mice injected with mouse or cow milk was similar but was less than the gain of the young of the non-injected control mice. The weight gain of the young of the mothers receiving lipid-free cow milk was similar to that of the controls, whereas that of the young of mothers receiving lipid-free cow milk with added lipids was again less than in the control group. There was no difference in litter mortality rate between the controls and the group treated with lipid-free cow milk, nor between the groups treated with mouse, cow and lipid-free cow milk with added lipids; the mortality, however, in the three latter groups was higher than in the two former ones. The injection of milk decreased milk yield. The effect of the injection of milk was observed within 24 h of the first injection.
The results suggest that milk secretion is impaired by the injection of milk. The effect may be ascribed to the lipid fraction of milk or to some unknown chemical factor within it. The rapid onset of the effect suggests that it is not mediated by an immunological reaction.
THE PROGESTERONE CONCENTRATIONS IN THE PERIPHERAL PLASMA OF THE MINK (MUSTELA VISON) DURING PREGNANCY
Authors: MØLLER O. M. 
Published: December 2008

SUMMARY
In mink bitches mated once, the progesterone levels in plasma remained at the basal level (< 8 ng/ml, i.e. comparable with the progesterone levels in anoestrous mink) during the first days after coitus. The duration of this lag period varied from 10 to about 20 days, and was found to correspond with the length of gestation. However, in general a gradual increase was observed beginning about 40 days before parturition with a maximum plasma progesterone concentration (63–105 ng/ml) from 10 to 25 days later on. After the peak value had been attained the plasma progesterone concentration declined gradually to the day of parturition and was low ( < 10 ng/ml) at parturition and afterwards. The progesterone values and profiles obtained from females mated twice corresponded with those obtained from females mated once. The increase in progesterone, however, began a few days after the second mating.
The developmental stages of the foetuses corresponded clearly with the progesterone profile.
In three mated females which failed to give birth a slow increase in progesterone concentration was observed beginning about 15 days post coitum. In these bitches the progesterone concentration reached a plateau (30–45 ng/ml) between day 30 and day 40 post coitum, after which a slow decline was observed. The period when the progesterone concentrations were increased above the basal level lasted about 40 days even in the females which did not give birth.
EFFECT OF OESTROGEN UPON PARTURITION, MATERNAL BEHAVIOUR AND LACTATION IN OVARIECTOMIZED PREGNANT RATS
Authors: CATALÁ SILVIA , DEIS R. P. 
Published: December 2008

SUMMARY
Ovariectomy of rats on day 20 of pregnancy impaired parturition and lactation. All rats showed prolonged delivery with many foetuses born dead and the mothers were unable to rear the young. Treatment with oestradiol benzoate (0·5 or 1 μg) in a single dose permitted normal delivery and lactation when the hormone was injected immediately after ovariectomy. Oestrogen administered the day after ovariectomy was not effective. The administration of prolactin and corticotrophin to ovariectomized pregnant rats did not prevent abnormal parturition but lactation improved in 50% of the mothers. A group of animals ovariectomized on day 20 was treated with oxytocin every 2 h on day 22 starting at 08.00 h. This treatment did not facilitate parturition and lactation. Maternal behaviour, which was always present in the other groups, was also impaired by this treatment. When ovariectomy was performed on the evening of day 21 of pregnancy, a partial impairment of parturition was observed but lactation was normal in seven out of eight rats. The results indicate that oestrogen is essential near term for normal parturition and lactation. The absence of the steroid may make the uteri less sensitive to oxytocic substances and also affect milk ejection.
FURTHER STUDIES ON CHOLINERGIC MECHANISMS AND HORMONE-ACTIVATED COPULATORY BEHAVIOUR IN THE FEMALE RAT
Authors: LINDSTRÖM L. H. 
Published: December 2008

SUMMARY
Previous experiments have demonstrated that the cholinergic compounds pilocarpine and oxotremorine decrease the oestrogen plus progesterone-activated lordosis response in the female rat. The present study showed that pilocarpine and oxotremorine, in doses which did not interfere with overt behaviour, also facilitated the lordosis response when given 48 h after oestrogen and thus substituted for the progesterone treatment. This effect could be counteracted by atropine but not by methylatropine pretreatment. The facilitating effect was not obtained after adrenalectomy or hypophysectomy. It is therefore suggested that the facilitating effects of the cholinergic compounds on copulatory behaviour in the oestrogen-treated female rat is mediated by pituitary—adrenal mechanisms.
ANDROGEN-DEPENDENT SYNTHESIS OF α2u GLOBULIN IN THE RAT: ROLE OF THE PITUITARY GLAND
Authors: ROY A. K. 
Published: December 2008

SUMMARY
Hypophysectomy completely abolished the androgen-dependent synthesis of α2u globulin in adult rats. Experiments with adrenalectomized and thyroidectomized adult male rats showed that these endocrine ablations also reduced the daily urinary output of α2u globulin to about 10% or less than those of the pre-operative values. The effects of adrenalectomy and thyroidectomy on α2u output could be reversed to normal with the supplementation of corticosterone and thyroxine respectively. However, none of the pituitary hormones administered alone or along with testosterone was able to reverse the effect of hypophysectomy. Simultaneous treatment with growth hormone, corticosterone and thyroxine along with testosterone was required for the complete reversal of the effect of hypophysectomy. It is concluded that the androgenic induction of α2u globulin is dependent on the synergistic effects of growth and developmental hormones such as growth hormone, thyroxine and corticosterone.
A COMBINED BIOCHEMICAL AND HISTOLOGICAL STUDY ON THE ISLETS OF LANGERHANS IN THE GENETICALLY OBESE HYPERGLYCAEMIC MOUSE AND IN THE LEAN MOUSE, INCLUDING OBSERVATIONS ON THE EFFECTS OF STREPTOZOTOCIN TREATMENT
Authors: FINDLAY J. A. , ROOKLEDGE K. A. , BELOFF-CHAIN ANNE , LEVER J. D. 
Published: December 2008

SUMMARY
The biochemical parameters of blood glucose, serum insulin and pancreatic insulin and glucagon were determined after single injections of the diabetogenic agent streptozotocin and in untreated animals from a strain of genetically obese mice and their lean litter-mates. Histological observations on α and β islet cells were also made in these animals by employing the phosphotungstic acid—haematoxylin and aldehyde—fuchsin staining techniques.
In untreated obese mice, endocrine hyperactivity was indicated by the presence of exceptionally large, highly vascular islets and by duct cell-islet metaplasia.
After streptozotocin injection, approximately half of the lean mice showed extensive β-cell necrosis and these animals became hyperglycaemic and hypoinsulinaemic with a much reduced pancreatic insulin over a long term. The remaining treated lean mice, whose biochemical parameters did not differ significantly from normal, showed little or no evidence of islet damage. The response of obese mice to streptozotocin treatment was less clear-cut than that of lean animals. Essentially similar histological changes were observed, though these were not consistently correlated with biochemical data. There was histological and biochemical evidence of islet cell recovery from the effects of the drug both in lean and in obese mice, and in all hyperglycaemic animals with initial severe islet damage a marked α-cell response was observed, namely an increased proportion of α cells and their random deployment throughout the islets.
THIOCYANATE ION IN SERUM AS AN INTERFERING FACTOR IN THE IN-VITRO BIOASSAY OF THYROTROPHIN
Authors: BOURKE J. R. , MANLEY S. W. , HAWKER R. W. 
Published: December 2008

SUMMARY
The presence of thiocyanate ion in human and rat serum has been shown to account entirely for the non-specific activity of sera in an in-vitro bioassay for thyrotrophin. Thiocyanate was identified by its chromatographic behaviour on Sephadex G-10, G-15 and G-25, and by the ferric nitrate and cobalt nitrate tests. Cigarette smoking increased mean serum thiocyanate levels (as NaSCN) from 0·2 to 0·56 mg/100 ml. It is suggested that serum thiocyanate levels are sufficient to inhibit significantly iodide trapping in vivo and that these findings may be relevant to the non-specific responses observed with other in-vitro bioassays based on radioiodine dynamics.
EFFECT OF DECAPITATION ON THE DEVELOPMENT OF INSULIN SECRETION IN THE FOETAL RABBIT
Authors: JACK P. M. B. , MILNER R. D. G. 
Published: December 2008

SUMMARY
One rabbit foetus in a litter was decapitated on day 24 of gestation. On day 29 the litter was killed and blood was collected from all foetuses for the measurement of plasma insulin concentration. The pancreas of the decapitated foetus and that of the control litter-mate with the nearest headless body weight were cut into pieces and incubated in a physiological buffer containing 0·6 or 3·0 mg glucose/ml. The pancreas of the decapitated foetus secreted significantly more insulin than that of the control foetus in either concentration of glucose in the medium. Higher insulin secretion from the decapitated foetus persisted for 4·5 h of incubation and was demonstrable in both the first 5 and subsequent 25 min of incubation when the pancreas was initially transferred to incubation medium containing 3·0 mg glucose/ml. The mean plasma insulin concentration of the foetuses decapitated on day 24 was higher on day 29 than that of the control foetuses but there was no significant difference between the concentration of insulin in the pancreas of the two groups of animals. The results indicate that removal of the foetal head influences the intrauterine development of the rabbit β-cell.
HORMONAL SPECIFICITY IN THE SUPPRESSION OF SEXUAL RECEPTIVITY OF THE FEMALE GOLDEN HAMSTER
Authors: CONIGLIO LINDA P. , PAUP D. C. , CLEMENS L. G. 
Published: December 2008

SUMMARY
Oestrogen—progesterone-induced lordosis behaviour was suppressed in female hamsters which received neonatal treatment with testosterone propionate or diethylstilboestrol. No suppression of lordosis was observed in females which received neonatal treatment with testosterone, androsterone or control substances. In addition, the ano—genital distance and diameter of the vaginal orifice were increased in females treated with testosterone, testosterone propionate, androsterone or diethylstilboestrol. However, testosterone, testosterone propionate and androsterone had a greater effect on ano—genital distance than did diethylstilboestrol. Possible mechanisms for the defeminizing action of the hormones administered were discussed.
VASOPRESSIN AND MILK SECRETION: LACK OF EFFECT OF LOW DOSES
Authors: PEAKER M. , LINZELL J. L. 
Published: December 2008

SUMMARY
The infusion of vasopressin in amounts thought to be released during water deprivation had no effect on the rate of milk secretion or on milk composition. These results do not support the conclusions of Konar & Thomas (1970) that vasopressin at physiological levels affects the rate of milk secretion, since the doses they used were very much higher and probably outside the physiological range. The implications of these findings and their possible adaptive significance are discussed.
THE METABOLISM OF TESTOSTERONE BY HUMAN MALE SCALP SKIN
Authors: BINGHAM K. D. , SHAW D. A. 
Published: December 2008

SUMMARY
[4-14C]Testosterone was incubated with human male scalp skin and the metabolites identified as 5α-androstane-3α, 17β-diol, androsterone, epiandrosterone, dihydrotestosterone, androstenedione and androstanedione. A metabolite not previously reported from incubations of human skin with androgens was isolated and is probably a steroid ester.
One bald and one hairy scalp biopsy specimen from each of five subjects were incubated with [4-14C]testosterone for 1 h and the radioactivity of each metabolite was measured after separation by thin-layer chromatography. Both the uptake and metabolism of testosterone were greater in bald skin than in hairy skin. Little difference in the percentage of each metabolite in the total metabolite pool was found between bald and hairy skin from the same subject and skin from different subjects. This demonstrated that male pattern baldness was not accompanied by gross changes in testosterone metabolism. The main finding was that bald skin contained increased amounts of 5α-reduced metabolites.
URINARY PREGN-5-ENE-3α, 16α,20α-TRIOL IN ADRENAL DYSFUNCTION
Authors: FANTL VERA , BOOTH MOLLIE , GRAY C. H. 
Published: December 2008

SUMMARY
Pregn-5-ene-3α, 16α,20α-triol in amounts from 50 to 220 μg/24 h was found in the urine of normal adult men and women. Excretion within this range was also found in five adult women of whom two had congenital adrenal hyperplasia, one had Cushing's disease, one was hirsute and infertile and one was obese. Except for one patient, who excreted amounts within the normal range, subjects with adrenal carcinoma excreted up to 15 mg of this steroid/24 h.
THE STIMULATION BY PROLACTIN AND GROWTH HORMONE OF FATTY ACID SYNTHESIS IN EXPLANTS FROM RAT MAMMARY GLANDS
Authors: HALLOWES R. C. , WANG D. Y. , LEWIS D. J. , STRONG C. R. , DILS R. 
Published: December 2008

SUMMARY
Explants of mammary glands and of subcutaneous body fat from sexually mature virgin and from 19-day pregnant Sprague-Dawley rats and of mammary gland from 5-day lactating Sprague-Dawley rats, were maintained in organ culture for up to 96 h. The effects of insulin (I), corticosterone (B), prolactin (P) and growth hormone (G) on the rate of fatty acid synthesis were measured by the incorporation of [14C]acetate. The effect of these hormones on the synthesis of various carbon-chain length fatty acids was measured by radio gas-liquid chromatography.
Explants from both tissues had a reduced rate of fatty acid synthesis after 24 h in medium 199, but this rate was increased by the addition of insulin. In explants of subcutaneous fat from virgin rats, the rate was further increased by culture in IBP or IBG, but this increase was not blocked by actinomycin D. In explants from subcutaneous fat of 10-day pregnant rats the rate was not increased by the addition of B, P or G to the insulin-containing medium. In mammary gland explants from virgin rats, IBP stimulated a greater rate of fatty acid synthesis than did insulin alone. In mammary gland explants from 10-day pregnant rats, the rate of fatty acid synthesis was increased by both IBP and IBG. In mammary gland explants from rats on the 5th day of lactation, both IBP and IBG increased the rate of fatty acid synthesis compared with insulin or IB. Actinomycin D blocked the increased fatty acid synthesis produced by prolactin or growth hormone but not that produced by insulin alone.
Mammary gland explants from rats on the 5th day of lactation were cultured for the first 4 h after excision in medium 199 that contained sodium [14C]acetate. Sixty-eight per cent of the 14C was incorporated into C8-C12 fatty acids. In explants from subcutaneous fat none of the hormones tested increased 14C incorporation in these fatty acids. In mammary gland explants from virgin or 10-day pregnant rats, insulin, corticosterone and prolactin increased the incorporation in these fatty acids. Growth hormone was less efficient than prolactin in stimulating C8-C12 fatty acid synthesis.
SOME EFFECTS OF THYROID DISEASE ON NEUTRAL STEROID METABOLISM
Authors: BEALE R. N. , CROFT D. , POWELL DENISE 
Published: December 2008

SUMMARY
Gas—liquid chromatography was used to compare the urinary levels of 18 neutral steroid metabolites in normal, hyper- and hypothyroid subjects. Numerous significantly abnormal parameters were observed in both disease states.
In hyperthyroidism the ratios of total androsterone: total aetiocholanolone and of their aglycones were increased. Total 17α-hydroxycorticosteroids were moderately increased largely because of augmented levels of some major metabolites, e.g. the summed cortolones, with only small decreases in others, e.g. tetrahydrocortisol. The percentage contribution of tetrahydrocortisol to its group of eight related metabolites was, however, profoundly reduced.
In hypothyroidism the excretions of all major glucosiduronates and sulphates of the 11-deoxy-17-oxosteroid group were greatly, and some profoundly, reduced, with a marked decrease in the ratio of the aglycones androsterone:aetiocholanolone. Total 17α-hydroxycorticosteroids were moderately decreased, largely because of low outputs of tetrahydrocortisone and of the summed cortolones. There was a profound decrease in the percentage contribution of 5α-tetrahydrocortisol.
Explanations of the observations are attempted in terms of hypothetical changes in the activities of certain steroid-metabolizing enzymes.
THE INFLUENCE OF EXTEROCEPTIVE STIMULI AND PHEROMONAL FACILITATION OF OVULATION IN DIFFERENT STRAINS OF MICE
Authors: ELEFTHERIOU B. E. , CHRISTENSON C. M. , ZARROW M. X. 
Published: December 2008

SUMMARY
Pheromonal facilitation of pregnant mare serum gonadotrophin (PMSG)-induced ovulation was compared in four strains of immature mice after exposure to adult intact males, castrated males, castrated males after treatment with testosterone propionate, or exposure to adult females. Psychobehavioural modification of their response was studied after transferring PMSG-injected females between cages, or after their exposure to either electric foot shock or adverse auditory stimuli. Significant facilitation of the average number of ova released and percentage of mice ovulating was found in females of the strains C3HeB/FeJ and BALB/cJ, but not in strains DBA/2J and C57BL/6J after exposure to adult males. Exposure to castrated males treated with testosterone propionate resulted in a response essentially the same as that to intact males, whereas exposure to adult females inhibited ovulation uniformly in all the strains studied except BALB/cJ. Auditory stimuli prevented this phenomenon in strains C3HeB/FeJ and C57BL/6J, but an obvious facilitation was observed in strains BALB/cJ and DBA/2J. Electric shock facilitated ovulation in strain DBA/2J but not in the other three strains.
CHARACTERIZATION OF THE SPECIFIC ANDROGEN RECEPTORS IN THE HUMAN PROSTATE GLAND
Authors: MAINWARING W. I. P. , MILROY E. J. G. 
Published: December 2008

SUMMARY
A search has been conducted for specific androgen-binding proteins in soluble extracts of normal human prostate tissue and in surgical samples removed at retropubic prostatectomy for benign prostatic hyperplasia. Proteins with a particularly high affinity for a metabolite of testosterone, 5α-dihydrotestosterone, have been identified in studies on the binding of 3H-labelled steroids in vitro. The 5α-dihydrotestosterone-protein complexes have been partially characterized using sucrose density gradient centrifugation and gel-exclusion chromatography. The androgen receptors in the human prostate gland are remarkably similar to those previously described in the accessory sexual glands of experimental animals. These findings have been confirmed by the analysis of extracts of hyperplastic prostate glands labelled by the administration of [3H]testosterone in vivo. No attempt was made to correlate the degree of binding with the histological appearance of the specimens of hyperplastic prostate or to determine whether the receptors were principally present in the hyperplastic nodules. Such androgen-binding proteins were not present in serum, skeletal muscle or adipose tissue. The possible relevance of these findings to the onset of clinical disorders in the human prostate gland is briefly discussed.
LABILITY OF HUMAN PITUITARY FOLLICLE-STIMULATING HORMONE TO MILD ACID TREATMENT
Authors: KENNEDY J. F. , CHAPLIN M. F. 
Published: December 2008

SUMMARY
The lability of human pituitary follicle-stimulating hormone (FSH) to dilute hydrochloric acid was studied. Hydrolysis at pH 1·0 and 20 °C for 3 h abolished the biological activity of the hormone in vivo, but hydrolysis at pH 0·0 and 20 °C for 3 h gave rise to fragments of low molecular weight which retained immunological activity. In contrast, the weakest hydrolysis conditions which removed all the N-acetylneuraminic acid units were pH 2·0 at 80 °C for 50 min. Under these conditions, 75% of the fucose units but none of the other monosaccharide units of FSH were liberated. The results demonstrate the considerable lability of FSH to mild acid and provide an example of a glycoprotein, acid hydrolysis of which is unsuitable for removal of N-acetylneuraminic acid and fucose units selectively.
THYROTROPHIN SECRETION FROM RAT PITUITARY AUTOGRAFTS INFUSED WITH SYNTHETIC THYROTROPHIN RELEASING FACTOR
Authors: AVERILL R. L. W. , EVANS J. S. 
Published: December 2008

SUMMARY
Thyroidal uptake and release of 131I were used to study the response of pituitary autografts to locally infused synthetic thyrotrophin releasing factor (TRF) and porcine median eminence extract (MEE). Thyroidal release rates of 14% 131I/24h were maintained during continuous infusion of grafts with MEE (equivalent to 4 hypothalami/day) while 12·6% 131I/24 h was lost from thyroids of rats whose pituitary autografts were infused with 1000 ng synthetic TRF/day. Infusion of autografts with 5, 50 and 250 ng synthetic TRF/day resulted in lower, but dose-dependent, thyroidal responses suggesting that synthetic TRF could induce thyrotrophin (TSH) synthesis in the grafts.
At all doses of TRF, thyroidal 131I release was significantly increased by daily injection of cortisone (2 mg s.c.).
Local TRF stimulation of TSH release from pituitary grafts significantly increased the dose of thyroxine (T4) needed to decrease thyroid activity, and while 1·0 μg T4/100 g depressed activity in rats receiving saline infusions, 1·7–2·7 μg T4/100 g was needed to inhibit 131I release in rats receiving 250 ng TRF/day, and 3 μg T4/100 g was needed by rats receiving 1000 ng TRF/day.
Continuous TSH infusion (25–28 mu./day) into hypophysectomized rats induced thyroidal 131I release at rates similar to those in rats with TRF-stimulated pituitary autografts.
It is suggested that while synthetic TRF can enhance TSH synthesis in the pituitary its effects on TSH synthesis may normally be potentiated by other humoral substances.
THE CONTROL OF ARGININE-INDUCED INSULIN SECRETION IN THE RAT: THE ROLE OF CATECHOLAMINES
Authors: BACCHUS R. A. , MEADE L. , HUTCHINSON J. S. M. , LONDON D. R. 
Published: December 2008

SUMMARY
The effect of alterations in catecholamine metabolism on arginine-induced insulin release was studied in the anaesthetized rat. Alpha-methyl-p-tyrosine, which inhibits catecholamine synthesis, guanethidine, which prevents catecholamine release, and reserpine, which depletes catecholamine stores, all enhanced the secretion of insulin and reduced the rise in blood glucose after the amino acid load. Adrenalectomy, with or without corticosterone replacement, had a similar effect. Adrenaline inhibited the insulin response to arginine. It was concluded that in the rat, adrenergic mechanisms modulate the insulin response to arginine.