bluuebunny/crossref_metadata_2025_split huggingface dataset:
SERUM FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE LEVELS IN MALE RATS WITH EXPERIMENTALLY INDUCED DAMAGE OF THE GERMINAL EPITHELIUM
Authors: DEBELJUK L. 
Published: December 2008

SUMMARY
The effect of the depletion of germinal cells from the seminiferous tubules on serum follicle-stimulating (FSH) and luteinizing (LH) hormones was studied in young male rats. A single administration of 1-(N,N-diethylcarbamylmethyl)-2-4-dinitropyrrole (ORF 1616) seemed to damage primary spermatocytes and especially young spermatids. Whenever young spermatids (stages 1–8) were absent or at least decreased in number, a significant increase in serum FSH, and in some cases serum LH, was detected. The administration of another drug, bis(dichloroacetyl) diamine (WIN 18446) for 21 consecutive days induced a depletion of primary spermatocytes in the seminiferous tubules, which was followed by a depletion of spermatids, due to the lack of spermatocytes to generate them. By the time the seminiferous tubules showed partial or total disappearance of young spermatids, serum FSH and in some cases also serum LH levels were significantly raised. It is concluded that the germinal epithelium of rat testes exerts some kind of control on serum gonadotrophin levels. Young spermatids seem to be involved in this regulation.
ANDROGENIZATION: ALTERATIONS IN THE MECHANISM OF OESTROGEN ACTION
Authors: LOBL R. T. 
Published: December 2008

SUMMARY
Total nuclear uptake of oestradiol, specific nuclear binding of oestradiol and oestrogeninduced proteins were studied in the uterus of female Sprague–Dawley rats injected on postnatal day 3 with sesame oil or with 1·25 mg of testosterone propionate in sesame oil (androgenization). Total uptake of radioactivity was lower than normal in nuclei from uterine homogenates of androgenized females but was increased by the addition of excess cytosol from normal uterus. These data suggest that androgenization increases the uterine cytosol proteins which inhibit translocation of oestradiol to the cell nucleus. Androgenization also reduced specific (5 S) nuclear binding of oestradiol and the formation of oestrogeninduced proteins.
EFFECTS OF LESIONS OF THE PITUITARY STALK ON LACTATION IN THE RABBIT
Authors: COWIE A. T. , TINDAL J. S. 
Published: December 2008

SUMMARY
The daily milk yields and the yields of fat, lactose and protein in milk were studied in New Zealand White rabbits in which the pituitary stalk and its portal vessels had been interrupted by a radiofrequency lesion placed during the second or third weeks of lactation. In comparison with yields from control rabbits, i.e. animals in which the lesion did not completely interrupt the stalk, the yields of milk and of milk constituents were depressed after interruption of the stalk on day 11 or day 15 of lactation. When the lesion was placed on day 19 of lactation the milk yield was depressed whether or not the stalk was completely disrupted; the decline in yield exaggerated the normal decline of yield that occurs at this stage of lactation. After interruption of the pituitary stalk changes in milk composition were associated with changes in milk production, no evidence being obtained to support an earlier suggestion that section of the pituitary stalk in the rabbit alters the milk composition whilst leaving milk output unaffected.
INCREASE IN PLASMA TESTOSTERONE CONCENTRATION AFTER INJECTION OF ADRENOCORTICOTROPHIN INTO THE BOAR
Authors: LIPTRAP R. M. , RAESIDE J. I. 
Published: December 2008

SUMMARY
Injection of a 'rapid-acting' preparation of porcine adrenocorticotrophic hormone (ACTH) into three boars resulted in a rapid rise in plasma testosterone levels which accompanied the expected rise in plasma corticosteroids. Urinary dehydroepiandrosterone (DHA) levels were measured in one boar and were found to be raised also. The results suggest that the effect involved enhanced testicular steroid activity and was related to the dosage of ACTH employed. This action of ACTH is thought to be mediated through the adrenal cortex since injection of cortisol elicited a rise in testosterone similar to that observed after injection of ACTH. ACTH had no effect on testosterone levels in a castrated boar. When a 'longacting' preparation of ACTH was administered to two boars twice daily for 5 days, testosterone levels were depressed. It was concluded that ACTH may bring about an increase or a decrease in plasma testosterone levels in the boar depending upon the length of time increased levels of ACTH are present in the circulation.
GENETIC DIFFERENCES IN THE CORTISOL CONCENTRATION OF THE ADRENAL AND OTHER TISSUES OF WHITE AND COLOURED GUINEA-PIGS
Authors: FAZEKAS A. T. A. , HOMOKI J. , TELLER W. M. , GAUS W. 
Published: December 2008

SUMMARY
The effect of genetic difference (white v. coloured) on the cortisol content of ten different organs and tissues, including the adrenals, of white and coloured guinea-pigs of both sexes and of different ages was studied by protein-binding techniques. Tissue cortisol concentration was significantly higher in all the tissues and adrenals of white animals of both sexes compared with coloured animals. The difference in tissue cortisol content between white and coloured animals was higher before (range 41·5–134·%) than after puberty (range 10·1–82·5%). The age-dependent decrease of cortisol concentration in different tissues and adrenals in adults was more marked in white guinea-pigs of both sexes (mean 30·6%, range 0·0–71·5%) than in coloured (mean 16·9%, range 0·0–63·1%). In adult animals the liver contained significantly 11·8–36·4%) more cortisol than in prepubertal animals. This pattern was the same in white and coloured guinea-pigs of both sexes.
RE-INTRODUCTION AND EVALUATION OF AN ACCURATE, HIGH CAPACITY BIOASSAY FOR MELANOCYTE-STIMULATING HORMONE USING THE SKIN OF ANOLIS CAROLINENSIS IN VITRO
Authors: TILDERS F. J. H. , VAN DELFT A. M. L. , SMELIK P. G. 
Published: December 2008

SUMMARY
A simple and rapid assay for the quantitative determination of melanocyte-stimulating hormone (MSH) activity, using skin fragments of the lizard Anolis carolinensis in vitro, is described in detail. This assay, in which a quantal response (e.g. induction of a brownishgreen colour) can be detected by visual observation, allows determination of MSH activity in up to 50 samples/day by one person, using the skin of one lizard. The mean dose found to induce this colour change was 0·15 ng synthetic α-MSH/ml (range 0·02–0·5 ng/ml). The assay shows high accuracy, reproducibility and specificity. Anterior and posterior lobe hormones as well as pituitary catecholamines do not interfere with the determination of pituitary MSH activity.
The method is compared with the assay using hypophysectomized frogs (Rana pipiens) in vivo. Determinations of MSH in pituitary extracts by both methods gave quantitatively similar results when determined with α-MSH as the reference substance. However, when β-seryl MSH was used as a reference, the two assays gave different results for the MSH activity of the pituitary extracts. This indicates that MSH from the rat pituitary gland has a biological activity similar to that of α-MSH rather than to that of β-seryl MSH.
ULTRASTRUCTURE OF THE MAMMARY GLAND IN LACTATING RATS AFTER LOCAL IMPLANTATION OF OESTROGEN
Authors: ZAMORA A. J. , MENDOZA A. S. , RAMIREZ V. D. 
Published: December 2008

SUMMARY
Cannulae containing oestrogen were implanted in the mammary glands of rats on the first day after parturition and lactation assessed by daily measurements of the litter weight. Sham-implanted and intact lactating rats were used as controls. A clear-cut inhibition of the milk yield was observed in the oestrogen-implanted group. Mammary tissue was processed for fine structural study after 4, 8 or 10 days. The initial phase showed milk stasis and secretion of colostrum progressively involving the alveoli and culminating in regression of the mammary tissue. Disappearance of myofilaments from the myoepithelial cells was consistently observed. Secretion of colostrum and mammary regression could be the result of the stasis produced by an abnormal dynamic state of the myoepithelial cell elicited by the steroid.
LEVELS OF LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, TESTOSTERONE AND DIHYDROTESTOSTERONE IN THE CIRCULATION OF SEXUALLY MATURING INTACT MALE RATS AND AFTER ORCHIDECTOMY AND EXPERIMENTAL BILATERAL CRYPTORCHIDISM
Authors: GUPTA D. , RAGER K. , ZARZYCKI J. , EICHNER M. 
Published: December 2008

SUMMARY
Plasma concentrations of LH, FSH, testosterone and dihydrotestosterone (DHT) have been measured in normal sexually maturing male rats from the age of 16–90 days. Between 16 and 25 days plasma testosterone levels were low, but rose suddenly on day 26. A similar increment occurred at the same time in plasma DHT levels, but this steroid reached its peak concentration later than testosterone. Plasma LH levels rose steadily from day 25 onwards, reaching their highest values on day 30. A marked increase in FSH levels was found on day 16, and a peak was reached on day 33 followed by a decline to a level characteristic of the adult. In addition, plasma levels of all these hormones were estimated in the male animals at various stages of development after orchidectomy and cryptorchidism. Four days after operation, the plasma levels of LH and FSH in the orchidectomized animals reached higher levels than those found in the intact animals, indicating the existence of a dynamic feedback relationship before puberty between gonadal steroids and pituitary gonadotrophic secretion. However, results from the experimental bilaterally cryptorchid animals, suggested that the gonadal steroid–gonadotrophic feedback relationship could not be the only factor initiating puberty.
COMPARISON OF THE CHARACTERISTICS AND OF THE HORMONAL CONTROL OF ENDOMETRIAL AND MYOMETRIAL PROGESTERONE RECEPTORS
Authors: LUU THI M. T. , BAULIEU E. E. , MILGROM E. 
Published: December 2008

SUMMARY
The characteristics of endometrial and myometrial progesterone receptor of guinea-pig were compared. Affinity for progesterone, hormone specificity, sedimentation properties (in oestrogen-primed animals), inhibition of binding by p-hydroxymercuribenzoate were found to be identical in both tissues. Differences were, however, observed in the hormonal control of the concentration of receptor. In all the situations studied, the concentration of receptors was higher in the endometrium than in the myometrium. In guinea-pigs ovariectomized at dioestrus the concentration was 3500 binding sites per diploid genome in the myometrium and 20300 in the endometrium; 1–3 days after oestradiol injection, this concentration was raised to 46000–38000 and 65000–83000 binding sites respectively. Thus the absolute rise was similar in both tissues but the relative increase was about 15-fold in the myometrium and only three- to fourfold in the endometrium. After injection of 2 mg progesterone, the concentration of receptor previously induced by oestrogen returned to very low values similar to those observed in non-hormonally treated controls.
This difference between endometrial and myometrial receptors could be due either to a faster turnover of the latter or to the existence of a stable non-hormonally controlled population of receptors, present only in the endometrium.
BIOSYNTHESIS OF GONADOTROPHINS BY RAT PITUITARIES IN VITRO
Authors: CHOWDHURY MRIDULA , STEINBERGER EMIL 
Published: December 2008

SUMMARY
A method has been developed for studying biosynthesis of FSH in the rat pituitary in vitro. Anterior pituitary glands were incubated with [3H]leucine; a specific and sensitive immunoprecipitation technique was used to isolate FSH from the pituitary homogenate. Total FSH content of the samples was measured by a double-antibody radioimmunoassay technique. Using this technique, a comparative study of LH and FSH synthesis in the same pituitary of adult male rats incubated for various intervals (0·5–6 h) was done. Increased incorporation of [3H]leucine into both LH and FSH with time was noted. The rate and amount of [3H]leucine incorporation into FSH was found to be higher than that into LH, indicating that either the rate of FSH synthesis is higher than that of LH or FSH has more leucine residues than LH. Greater susceptibility of LH to degradation by endogenous proteases during dialysis may also reflect less incorporation of [3H]leucine into LH. This method provides a reliable tool for evaluating FSH synthesis under various experimental conditions.
PERFUSION OF INTERCELLULAR SPACES IN THE PARS DISTALIS AND THEIR VARIATION WITH TIME OF DAY
Authors: QUAY W. B. 
Published: December 2008

SUMMARY
Microperfusion of the tissue parenchyma of regions of the rat pituitary gland with 1:1 dilutions of India ink revealed a network of fine intercellular spaces or canaliculi throughout the pars distalis. They were demonstrable in animals of all ages from 1·5 months to over 1 year, in both sexes, and at various times during the 24 h light–darkness cycle. However, 24 h rhythms were suggested in the radial perfusion distance (P < 0·05) and tissue density (P < 0·01) of the perfused canaliculi in adult male rats. The amplitude of the 24 h rhythmicity in these pituitary canaliculi was lower than that shown recently in pineal canaliculi of the same species. Structural regularity and evidence of rhythmic and physiologically correlated changes in the pituitary canaliculi suggest that they relate to natural features rather than being only artifactual, and that analysis of their possible functional significance is appropriate.
LEVELS OF CORTICOTROPHIN ANALOGUES IN THE BLOOD AFTER INFUSION INTO RATS
Authors: McMARTIN COLIN , PETERS JUDY 
Published: December 2008

SUMMARY
An isolated rat adrenal cell bioassay was used to measure blood concentrations in rats after infusion of synthetic human ACTH, corticotrophin-(1-24)-tetracosapeptide or [d-Ser1, Lys17, Lys18]corticotrophin-(1-18)-octadecapeptide amide. Lower blood levels were found with the 1-24 peptide than with human ACTH and the highest levels were found with the 1-18 peptide. These results suggest that the 1-24 peptide which is almost equipotent with natural ACTH in vivo may be more potent at the receptor and corroborate findings to this effect obtained with isolated adrenal cells. The high potency and prolonged action of the 1-18 analogue in vivo are also explained by these results.
Low arterial blood concentrations of the 1-24 peptide and human ACTH were found during infusion, suggesting that substantial inactivation must be occurring in a single passage through the lungs.
The effects of renal ligature on blood concentrations indicated that the kidney is involved in handling the 1-18 peptide and that human ACTH is also cleared by this organ. After infusion the fall in blood concentrations was biphasic. It is suggested that the rapid phase is due to clearance of peptides in the circulation which results in a fall to lower blood concentrations which are sustained by slow release of peptide from binding sites which act as a depot.
PITUITARY HORMONE RESPONSE TO BRAIN STIMULATION IN MAN
Authors: FRANKEL R. J. , JENKINS J. S. 
Published: December 2008

SUMMARY
Plasma cortisol, GH and LH responses to electrical stimulation of the orbital part of the frontal lobe and the cingulate area of the brain were studied in patients undergoing limbic leucotomy. In six out of 15 patients the plasma cortisol levels increased by 5·7–18·0 μg/100 ml after orbito-frontal stimulation whereas plasma GH values did not rise during this period. Plasma LH levels remained unchanged. No definite hormone responses could be attributed to stimulation of the cingulate area. It appears that the orbito-frontal area of the brain is concerned with augmenting the release of ACTH but not that of GH or LH.
ENDOCRINE CHANGES IN MALE SEXUAL DEVIANTS AFTER TREATMENT WITH ANTI-ANDROGENS, OESTROGENS OR TRANQUILLIZERS
Authors: MURRAY M. A. F. , BANCROFT J. H. J. , ANDERSON D. C. , TENNENT T. G. , CARR P. J. 
Published: December 2008

SUMMARY
The endocrine effects of drugs on two groups of 12 male sexual offenders in a special hospital were studied. In the first study benperidol, chlorpromazine and placebo were compared and in the second ethynyl oestradiol and cyproterone acetate were compared with no treatment.
In the first study there was no difference between the three drugs in their effects on plasma testosterone or luteinizing hormone (LH). In the second study cyproterone acetate produced a reduction in plasma testosterone, LH and follicle-stimulating hormone (FSH). Ethynyl oestradiol produced a rise in plasma testosterone and LH, and no change in FSH. Neither drug changed total plasma oestrogen levels. The unexpected effects of ethynyl oestradiol were attributed to an increase in sex hormone-binding globulin (SHBG) leading to a rise in bound, inactive testosterone. Direct measurement showed a two- to threefold increase in SHBG with ethynyl oestradiol treatment and no change in SHBG with cyproterone acetate treatment. In spite of these contrasting endocrine effects, ethynyl oestradiol, cyproterone acetate and benperidol produced similar behavioural changes.
RADIOIMMUNOASSAY OF PLASMA VASOPRESSIN IN PHYSIOLOGICAL AND PATHOLOGICAL STATES IN MAN
Authors: BEARDWELL C. G. , GEELEN G. , PALMER H. M. , ROBERTS D. , SALAMONSON L. 
Published: December 2008

SUMMARY
A radioimmunoassay method for the measurement of arginine-vasopressin (AVP) in human plasma has been developed which requires 5 ml of plasma and has a lower limit of detection of 1·8 pg/ml plasma. Arginine-vasopressin was found to be stable in whole blood for up to 1 h at room temperature and for at least 4 h at 4 °C, while in plasma stored at − 20 °C no loss was seen over 10 days. Dehydration and rehydration in normal subjects produced appropriate changes in AVP concentration but there was considerable variability in the levels attained by individual subjects and no obvious correlation with plasma osmolality. No consistent increase in plasma AVP concentration was seen on change of posture from the recumbent to the upright position. Vigorous exercise produced a marked rise in plasma AVP concentrations in most subjects which could not be attributed simply to an increase in plasma osmolality. Infusion studies with Pitressin in normal subjects showed a mean halflife of 6·4 min with an overall plasma clearance rate of 8·5 ml/min/kg body weight and a mean volume of distribution of 5·33 1. In patients with a biochemical picture suggestive of inappropriate antidiuretic hormone secretion, markedly raised plasma AVP concentrations were found only in patients with bronchial carcinoma.
PROGESTERONE, PROSTAGLANDIN F2α, AND OESTRADIOL IN THE UTERO-OVARIAN VENOUS PLASMA OF NON-PREGNANT AND EARLY, UNILATERALLY PREGNANT GUINEA-PIGS
Authors: BLATCHLEY F. R. , MAULE WALKER F. M. , POYSER N. L. 
Published: December 2008

SUMMARY
Levels of progesterone, prostaglandin F2α (PGF2α) and oestradiol in the utero-ovarian venous plasma of non-pregnant and early, unilaterally pregnant guinea-pigs were compared. Progesterone levels fell from day 12 to day 15 in the non-pregnant animals, while levels of PGF2α and oestradiol increased during this period. In contrast, in the pregnant guinea-pigs, progesterone levels remained high up to day 15 and PGF2α and oestradiol levels remained low in plasma from both the pregnant and non-pregnant sides. These findings support the hypothesis that the guinea-pig conceptus secretes an anti-luteolytic factor in early pregnancy, which reduces the amount of PGF2α produced by the uterus and released into the uterine veins and thereby allows luteal maintenance and continued progesterone secretion.
Oestradiol, in the presence of progesterone, is regarded as the physiological stimulus for normal uterine PGF2α synthesis and release. Consequently, the inhibition of ovarian oestradiol secretion seen in early pregnancy is probably at least part of the mechanism by which the anti-luteolytic factor produced by the conceptus reduces PGF2α synthesis by and release from the uterus.
EFFECTS OF PROGESTERONE AND SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE ON THE RELEASE OF LUTEINIZING HORMONE DURING SEXUAL MATURATION IN THE HEN (GALLUS DOMESTICUS)
Authors: WILSON SUSAN C. , SHARP P. J. 
Published: December 2008

SUMMARY
Single intramuscular injections of 0·5 mg progesterone/kg resulted in increased LH secretion in laying hens but not in pullets with completely undeveloped sexual organs. Injections of the steroid were first able to stimulate LH release 8–10 weeks before the onset of lay when the comb, ovary and oviduct had started to grow and basal plasma LH concentrations were beginning to rise. At this time, injections of 10 μg synthetic LH-RH/kg resulted in an incremental change in plasma LH levels of around 26 ng/ml. A similar incremental change was observed after giving the same dose of LH-RH to pullets with no signs of sexual development.
Three to four weeks before the first eggs were laid, basal plasma LH levels started to fall, the pituitary became progressively more insensitive to synthetic LH-RH and injections of 0·5 mg progesterone/kg resulted in a reduced LH response. Ten μg LH-RH/kg caused incremental changes in blood levels of LH of less than 5 ng/ml.
The final stage of sexual maturation occurred during the week before the onset of lay and was characterized by a rapid growth of large yolky ovarian follicles and a further fall in the sensitivity of the pituitary to synthetic LH-RH. However, injections of 0·5 mg progesterone/kg resulted in a prolonged release of LH.
These observations are discussed in relation to the maturation of the positive feedback mechanism by which progesterone stimulates the secretion of LH.
EFFECTS OF INJECTIONS OF MONOAMINE OXIDASE INHIBITOR OR SALINE INTO THE UTERUS IN LATE PREGNANCY ON UTERINE CATECHOLAMINE LEVELS RELATED TO ABNORMAL PARTURITION IN RATS
Authors: MALTIER J. P. , CAVAILLE F. 
Published: December 2008

SUMMARY
Injection of a monoamine oxidase (MAO) inhibitor (nialamide) into the uterus of an anaesthetized and laparotomized rat on day 20 of pregnancy severely disturbed parturition. Injection of the solvent (0·9% isotonic NaCl solution) at the same stage of gestation produced the same but less frequent disturbances. When the rats were injected on days 19 or 21, impairment was less marked than on day 20. Therefore, day 20 seems to be a critical period for the onset of parturition.
Injection of Ringer solution into the uterus on day 20 had effects analogous to those of saline injection at the same stage. Anaesthesia induced with ether, laparotomy of the pregnant rat on day 20, and handling of the uterine horns without injection of either Ringer or NaCl also disturbed parturition in 70% of the rats treated. Nevertheless, disorders were not as severe as those after injection. Laparotomy alone on day 20 did not disturb parturition.
The effects on parturition of a saline injection into the uterus on day 20 were greatly decreased when the injection was performed on pregnant rats adrenalectomized on day 14, or on pregnant rats pretreated on days 18 and 19 with an agent blocking the adrenergic β receptors (propranolol); 70–80% of the treated rats had normal deliveries.
In control rats, uterine catecholamine levels were markedly modified between days 21 and 22 of gestation. These changes did not occur in rats injected with MAO inhibitor or saline.