bluuebunny/crossref_metadata_2025 huggingface dataset:
SPECIFIC RELEASE OF BOVINE NEUROPHYSIN I DURING MILKING AND SUCKLING IN THE COW
Authors: LEGROS J. J. , REYNAERT R. , PEETERS G.
Published: December 2008

Using continuous blood sampling a specific release of neurophysin I without a significant release of neurophysin II was found during hand-milking and suckling in seven out of eight cows. Hand-milking appeared to be a slightly more powerful stimulus than suckling.
SHORT-TERM EFFECTS OF COPULATION, HUMAN CHORIONIC GONADOTROPHIN INJECTION AND NON-TACTILE ASSOCIATION WITH A FEMALE ON TESTOSTERONE LEVELS IN THE MALE RAT
Authors: PURVIS K. , HAYNES N. B.
Published: December 2008

Peripheral plasma testosterone levels in the male rat were increased above control levels 5 min after the first intromission with an oestrous female, or 8–10 min after first contact with the female. The levels remained raised for at least 30 min if copulation was allowed to continue. Intravenous injection of human chorionic gonadotrophin resulted in an increased peripheral concentration of plasma testosterone after 10–15 min and an increase of testosterone content of the testis 5–10 min after injection, indicating that the rat testis has a potential to respond rapidly to gonadotrophin. The results suggested that if the testosterone surge during copulation was gonadotrophin-dependent, it was initiated before the first intromission. Indeed, plasma testosterone levels were raised in male rats 5 min after being placed in the proximity of oestrous females but not allowed physical contact.
SOME EFFECTS OF VASOPRESSIN ON SEXUAL BEHAVIOUR AND SEMINAL CHARACTERISTICS IN INTACT AND CASTRATED RABBITS
Authors: KIHLSTRÖM J. E. , ÅGMO A.
Published: December 2008

The effect of intravenous injections of vasopressin upon sexual behaviour was studied in both intact and castrated, testosterone-treated rabbits. A high dose of vasopressin reduced the number of ejaculations and lengthened the latency to the first mount and ejaculation. A low dose of vasopressin had no significant effect on the sexual behaviour in either intact or castrated rabbits. The volume of ejaculates and the number of sperm cells were also determined. It was found that vasopressin (200 or 40 mu./animal) significantly increased both volume and sperm content in the ejaculates. The possibility that vasopressin is of physiological importance in male sexual functions is discussed.
THE EFFECT OF BETAMETHASONE ON GLUCOSE PRODUCTION AND ON GLUCONEOGENESIS FROM AMINO ACIDS IN SHEEP
Authors: REILLY P. E. B. , FORD E. J. H.
Published: December 2008

Primed continuous infusions of tracer amounts of [U-14C]glucose and of [U-14C]labelled mixed amino acids were used to measure plasma glucose and amino acid entry rates and to obtain an index of the incorporation of amino acid carbon into glucose by sheep before and 24 h after a single intramuscular injection of betamethasone.

Maximum hyperglycaemia occurred 24 h after administration of the steroid, but there was no significant change in arterial amino acid concentration. Mean glucose entry rate was significantly raised 24 h after steroid administration. The rate of incorporation of amino acid carbon into glucose also increased significantly. The increases in plasma glucose concentration and in glucose entry confirm the authors' previous results. The results also indicate that a significant proportion of the additional glucose entry is synthesized from amino acid carbon.
PROLACTIN RECEPTORS: CHARACTERISTICS OF THE PARTICULATE FRACTION BINDING ACTIVITY
Authors: FRANTZ W. L. , MacINDOE J. H. , TURKINGTON R. W.
Published: December 2008

Ovine 125I-labelled prolactin was incubated with a membrane-rich particulate fraction of mouse mammary gland and bound hormone was separated by centrifugation and washing. The experiments identified two types of binding activity: total binding and specific binding, the fraction of the total which could be displaced competitively by native prolactin but not by a number of other polypeptides. Two other lactogenic hormones, human chorionic somato-mammotrophin and human growth hormone, displaced 125I-labelled prolactin in proportion to their known intrinsic lactogenic activities. Binding of 125I-labelled prolactin was complete within 20 min at 4 or 37 °C. Scatchard analysis of the binding indicated an apparent dissociation constant (Kd) of approximately 9 × 10−9 mol/l and a concentration of binding sites of 15·5 × 10−13 mol/mg particulate protein. The greatest rate of specific displacement of bound 125I-labelled prolactin was observed at concentrations of prolactin between 50 and 250 ng/ml, a concentration range near the mid-point of the dose—response curve of casein induction in intact mammary cells. The saturating concentration of prolactin for specific binding to mammary particles was similar to that for casein induction in intact cells. The prolactin binding activity was sensitive to treatment with trypsin or heating at 70 °C, indicating its protein nature. These properties of the mammary prolactin binding activity are those required of a receptor for prolactin or other lactogens. Prolactin-specific binding activity was also found in particles from mouse liver, kidney, and midbrain and from the ovary, adrenal, and seminal vesicle of the rat. These results suggest a fairly widespread tissue distribution of the prolactin receptor, and potentially implicate prolactin in the hormonal regulation of these organs.
EFFECT OF GONADAL STEROIDS ON THE PITUITARY RESPONSIVENESS TO SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE IN THE MALE DOG
Authors: JONES GWYNETH E. , BOYNS A. R.
Published: December 2008

Intravenous injections of synthetic luteinizing hormone releasing hormone (LH-RH) stimulated LH secretion in male dogs. An i.m. injection of 0·025–2·5 mg oestradiol-17β given 2·5 h but not 24 h before administration of LH-RH blocked LH secretion. Diethylstilboestrol (2·5 mg) also blocked LH secretion but meso-dihydrodibutylstilboestrol (2·5 mg) was without effect. Testosterone (2·5 and 25 mg), dihydrotestosterone (2·5 mg), 5α-androstane-3α, 17β-diol (2·5 mg), 5α-androstane-3β, 17β-diol (2·5 mg), 5α-androstane-3α, 17α-diol (0·125 mg), 5α-androstane-3β, 17α-diol (0·125 mg) and progesterone (25 and 50 mg) did not prevent LH-RH stimulation of LH secretion.
THE EFFECT OF OXYTOCIN ON SPERM TRANSPORT IN OVARIECTOMIZED, OESTROGEN-TREATED RABBITS
Authors: MORTON D. B. , FITZPATRICK R. J.
Published: December 2008

Ovariectomized, oestrogen-primed rabbits were injected intravenously with varying doses of oxytocin immediately after insemination with a standardized inseminate. The does were killed 30 min after insemination and the number of spermatozoa in different segments of the genital tract was determined. The most significant finding was that when 80 mu. oxytocin were given, mass transport of semen into the uterus occurred. This suggests a coordinated response of the genital tract to a critical oxytocin stimulus which facilitates mass transcervical passage of fluids. However, when 80 mu. oxytocin were given to intact oestrous rabbits, no significant effect on sperm transport was detected.
THE EFFECT OF HUMAN PLACENTAL LACTOGEN ON ADIPOSE TISSUE LIPOLYSIS
Authors: STRANGE R. C. , SWYER G. I. M.
Published: December 2008

The lipolytic activity of human placental lactogen (HPL) was measured using adipose tissue pieces and free fat-cell suspensions. HPL in non-physiological concentrations stimulated lipolysis after a latent period of 2 h. The preincubation of tissue pieces with HPL in physiological concentrations (8 μg/ml) increased the rate of theophylline-stimulated lipolysis.
EFFECTS OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE ON PLASMA TESTOSTERONE LEVELS IN HYPOPHYSECTOMIZED AND IN INTACT IMMATURE AND ADULT MALE RATS
Authors: SAFOURY S. EL , BARTKE A.
Published: December 2008

The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on plasma testosterone levels were examined in hypophysectomized and in intact immature and adult male rats. The animals were injected with saline, LH, FSH, or both gonadotrophins twice daily for 3·5 days and were killed 3 h after the last injection. Plasma testosterone levels were measured by radioimmunoassay.

In immature hypophysectomized rats, plasma testosterone levels were not changed by treatment with LH, FSH or LH plus FSH. The weight of the testes and of the seminal vesicles was increased only in animals injected with both LH and FSH.

In adult hypophysectomized rats, LH caused the expected increase in plasma testosterone levels, while FSH injected alone had no effect. Plasma testosterone levels in rats treated with 5 μg LH and 20 μg FSH were significantly greater than those in animals given 5 μg LH alone. However, the same dose of FSH did not potentiate the action of 25 μg LH on plasma testosterone levels. In adult hypophysectomized rats the weight of testes was not affected by any of the treatments. The weight of the seminal vesicles was increased by the higher dose of LH and addition of FSH caused no further increase.

In intact immature and adult rats plasma testosterone levels and the weight of testes were not changed by any of the treatments. Seminal vesicle weight was increased only in adult rats treated with the higher dose of LH together with FSH.

The results demonstrate that FSH potentiates the action of low doses of LH on plasma testosterone levels in adult hypophysectomized rats and suggest that FSH may be involved in the regulation of androgen secretion by the rat testis.
THE EFFECTS OF OESTRUS AND EXOGENOUS OESTROGENS ON MILK SECRETION IN THE GOAT
Authors: PEAKER M. , LINZELL J. L.
Published: December 2008

Changes in the composition of the aqueous phase of milk were found to precede oestrus by up to 4 days in five out of six goats. However, the composition had returned to normal by the time oestrous behaviour was first observed. The alteration in composition was characterized by increases in milk sodium and chloride concentrations, and decreases in potassium and lactose; fat, protein and immunoglobulin concentrations were unaffected. These changes were also observed in autotransplanted (i.e. denervated) glands.

Large doses of exogenous oestrogens (to match the secretion rate in late pregnancy) administered to goats in anoestrus resulted in a significant fall in milk yield, increases in milk fat, protein, immunoglobulin and sodium concentrations, and a decrease in potassium. Chloride and lactose concentrations were not significantly changed except in some goats when the milk yield was severely affected 4 days after oestrogens were given i.m.

Possible hormonal mechanisms and the nature of the changes in the secretory epithelium before oestrus and as a result of oestrogen treatment are discussed.
INFLUENCE OF SEX AND AGE ON THE CORTISOL CONTENT OF PERIPHERAL TISSUES AND ADRENAL GLANDS IN THE GUINEA-PIG
Authors: FAZEKAS A. T. A. , HOMOKI J. , TELLER W. M.
Published: December 2008

The influence of age and sex on the cortisol content of adrenals, liver, kidney, lung, heart, spleen, muscle, cerebrum, brain stem and blood was studied in white guinea-pigs.

In prepuberal animals no significant difference between sexes was found in the cortisol content of different tissues. In adult female animals, the blood cortisol level was significantly higher than in the male animals. Significantly more cortisol was found in kidneys of adult male than of female animals.

In adult guinea-pigs, the cortisol content was lower in every tissue examined, except liver, compared with young animals. These differences were highly significant. In female guinea-pigs the decrease in tissue cortisol content with age was more pronounced than in male animals.
METABOLIC RESPONSE TO MALE HORMONE AND THYROID ACTIVITY IN THE INDIAN GARDEN LIZARD, CALOTES VERSICOLOR
Authors: CHANDOLA ASHA , KUMAR D. SURESH , THAPLIYAL J. P.
Published: December 2008

Thyroidectomy and orchidectomy led to significant reduction in the oxidative metabolism of isolated liver and skeletal muscle tissue (at 30 °C) in Calotes versicolor. Thyroxine and male hormone were shown to increase this parameter in intact and orchidectomized lizards respectively. The effects of thyroidectomy and orchidectomy on tissue oxygen uptake were not additive. It is supposed that by its effect on oxidative metabolism male hormone may be of a greater physiological importance for reptiles than for other vertebrates.

The present results show also that changes in environmental temperature can counteract the depressive effect of orchidectomy on the thyroid of this species of lizard.
THE RELATIONSHIP BETWEEN THE CHANGES IN THE INTERRENAL, GONADAL AND THYROIDAL TISSUE OF THE AIR BREATHING FISH, HETEROPNEUSTES FOSSILIS (BLOCH) AT DIFFERENT PERIODS OF THE BREEDING CYCLE
Authors: SINGH B. R. , THAKUR R. N. , YADAV B. N.
Published: December 2008

The interrenal tissue of the air-breathing fish, Heteropneustes fossilis, became hypertrophied during the breeding period. The interrenal cell cytoplasm became acidophilic and vacuolated, cytoplasmic granulation disappeared and the cell nuclei increased in size. The diameter of the nuclei varied from 2·07 to 3·12 μm in the non-breeding period while in the breeding season there was almost uniform enlargement (4·54 ± 0·36 μm). Variation in nuclear size was most pronounced during maturation of the gonads, i.e. in April. However, the size of larger nuclei (average diameter 6·53 ± 0·98 μm) was not significantly different from that of thesmaller nuclei (average diameter 4·61 ± 0·61 μm) during this period (P > 0·05).

The volume density of the cell components of the interrenal tissue nearly doubled in the breeding period but the relative proportions remained more or less the same. Glycogen granules, which appeared to be uniformly distributed in the interrenal cells in the non-breeding period, became aggregated and clumped in many parts of the cell during the breeding period. There was a clear increase in the chromaffin reaction in the chromaffin cells during the breeding period but the iodate reaction, indicating noradrenaline content, decreased considerably.

In the ovarian cycle there was a close relationship between gonadosomatic index, ova diameter and water temperature. There was a more than tenfold increase in the gonadosomatic index in the breeding period (1·30 in the non-breeding and 15·27 in the breeding periods). In males, the rise in the gonadosomatic index in the breeding period corresponded to that of the ovary in degree (0·22 in the non-breeding and 3·20 in the breeding periods).

In the non-breeding period the thyroid follicles were composed of squamous epithelium (epithelial height 1·2–2·2 μm) with a follicular diameter of 48–76 μm and the colloid completely filling the lumina of the follicles; features indicative of hypofunction of the gland. In the breeding period, the follicles were composed of cuboidal epithelium (epithelial height nearly three times that in the preceding period, 4·1–6·3 μm) follicular diameter was reduced (36–48 μm) and the colloid incompletely filled the lumina, thus suggesting normal or slight hyperfunction of the gland.
GENETIC STUDY OF THE EFFECTS OF [8-ARGININE]- AND [8-LYSINE]-VASOPRESSINS ON ADENYL CYCLASE ACTIVITY OF MOUSE KIDNEY
Authors: STEWART A. D.
Published: December 2008

Adenyl cyclase was measured in vitro in renal medullary homogenates from male mice of the Peru and CBA/FaCam strains. The basal activity of adenyl cyclase was increased on incubation with 30 mm-NaF and with varying concentrations of [8-arginine]-vasopressin (AVP) and [8-lysine]-vasopressin (LVP) up to 100 mu./ml. In both strains of mice, the maximal hormone activation was the same whichever vasopressin was used, and the same degree of stimulation was observed on incubation of homogenates with both hormones together. It is concluded that both hormones have the same intrinsic activity in this system, and are acting on the same population of receptors within each strain of mouse.

Half-maximal adenyl cyclase activation was achieved with 240 ± 50 (s.e.m.) μu. AVP/ml and 920 ± 160 μu. LVP/ml in homogenates from CBA/FaCam mice; and 240 ± 40 μu. AVP/ml and 1900 ± 250 μu. LVP/ml in Peru mice. These results are compared with previously reported potencies in these mice of the two vasopressins as antidiuretic agents in vivo. Whilst there is good agreement between results in vitro and in vivo with CBA/FaCam mice, there is a highly significant discrepancy with Peru mice. Explanations for these results, including the possibility that cyclic AMP may not be the sole mediator of the increased water permeability of the distal tubule induced by vasopressin, are discussed.
THE INFLUENCE OF SURGERY, TIME OF DAY, BLOOD VOLUME REDUCTION AND ANAESTHETICS ON PLASMA PROLACTIN IN OVARIECTOMIZED RATS
Authors: LAWSON D. M. , GALA R. R.
Published: December 2008

Plasma prolactin was measured by double antibody radioimmunoassay in ovariectomized rats bearing indwelling aortic catheters. Samples were obtained during recovery from ovariectomy and catheterization, at various times during the day, after blood volume reduction, and after administration of various anaesthetics. Prolactin levels were stabilized by day 3 after the operation but not by day 1. There was a significant (P < 0·01) increase in plasma prolactin during the afternoon in both ovariectomized rats and ovariectomized rats treated with 1 mg polyoestradiol phosphate. The magnitude of the response was more pronounced in the animals treated with oestrogen. Withdrawal of blood samples without subsequent replacement of fluid volume induced a significant (P < 0·05) decrease in plasma prolactin concentration after removal of only 1·2 ml blood within 20 min. No change was observed, however, when blood was replaced with saline. Ether and the intraperitoneal injection of sodium pentobarbitone produced prolonged increases in plasma prolactin whereas the intra-arterial administration of sodium pentobarbitone produced no change. Urethane and chloral hydrate caused only transient increases in plasma levels of prolactin regardless of the route of administration. Ketamine did not significantly alter plasma levels of prolactin.
THE ROLE OF PROLACTIN IN THE DEPRESSED OR 'BUFFERED' ADRENOCORTICOSTEROID RESPONSE OF THE RAT
Authors: SCHLEIN P. A. , ZARROW M. X. , DENENBERG V. H.
Published: December 2008

Lactating female rats are known to exhibit a reduced or 'buffered' plasma corticosterone response to stress. The depressed response is a post-partum phenomenon seen only in the lactating rat with pups, since a lactating rat whose pups have been removed for 8 days gives a normal response to ether stress. Thus it appears that lactation may be necessary for a reduced response to stress, and the reappearance of the normal response coincides with the time when the animal resumes its oestrous cycle. Maternal behaviour by itself could be ruled out as a causative factor since a normal adrenal response was seen in virgin rats which had been sensitized to pups.

A depressed corticosteroid response to ether stress was obtained after ovariectomy or treatment with prolactin (2 mg/day for 5 days). However, the effect of ovariectomy on plasma corticosterone levels after ether stress could be reversed by the injection of 5 μg oestradiol benzoate daily for 5 days.

The minimum effective dose of dexamethasone phosphate that was necessary to prevent increased plasma corticosterone levels after ether stress in the normal female rat was 400 μg/100 g body weight whereas a lactating rat required only 6·25 μg and a virgin rat treated with prolactin required 25 μg. It is apparent that prolactin is acting, in part at least, to increase the sensitivity of the negative feedback system.
PROGESTERONE AND OESTRADIOL-17β CONCENTRATIONS IN THE PERIPHERAL PLASMA DURING PREGNANCY IN THE MOUSE
Authors: McCORMACK J. T. , GREENWALD G. S.
Published: December 2008

The concentration of progesterone and oestradiol-17β in peripheral plasma was determined by radioimmunoassay on each day of pregnancy in the mouse. The progesterone concentration, low on days 1 and 2, correlated with the histological development of the corpora lutea. Progesterone levels during the first half of pregnancy rose to a peak on day 6 with a significant decrease (P < 0·02) on day 7. Peripheral progesterone concentration during the second half of pregnancy rose on days 12–13 with a peak on days 14–17, and declined after day 17, 3 days before the onset of parturition.

Oestradiol-17β concentrations were high on day 1, declined precipitously to low levels on days 2 and 3 recovering slightly on day 4. The levels then fell and remained low from day 5 to days 15–16, when there was a significant increase in oestradiol-17β concentration which continued until day 20.
INHIBITION AND MAINTENANCE OF SPERMATOGENESIS IN RATS IMPLANTED WITH POLYDIMETHYLSILOXANE CAPSULES CONTAINING VARIOUS ANDROGENS
Authors: BERNDTSON W. E. , DESJARDINS C. , EWING L. L.
Published: December 2008

Polydimethylsiloxane (PDS) capsules providing surface areas of 50, 75, 100, 200, 400 and 2000 mm2 were filled with testosterone, testosterone cypionate (TC), or testosterone propionate (TP) and were implanted (s.c.) into sexually mature rats for 56 days to determine the efficacy of this mode of androgen administration in suppressing or maintaining spermatogenesis. Rats that received 75 mm2 capsules of TP and 200 mm2 capsules of testosterone or TC were azoospermic and had a 45–50% reduction in testicular weight. Moreover, immunoreactive serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations declined eightfold below control values, but plasma testosterone titres and the dry weight of the accessory sex glands were not affected (P > 0·10). Conversely, 2000 mm2 capsules of testosterone, TC or TP maintained testicular weight and induced accessory sex gland hypertrophy as well as a five- to eightfold increase in the concentration of plasma testosterone. The relative number of germ cells at stage VII of the cycle of the seminiferous epithelium was not affected (P > 0·15) by 2000 mm2 testosterone capsules even though immunoreactive serum LH and FSH concentrations remained at least eight-fold below control values. Similar implants containing TC or TP maintained germ cell numbers within 83% of control testes. The results establish that PDS capsules releasing 'low' doses of testosterone, TC or TP induce azoospermia without affecting plasma testosterone concentration or accessory sex gland weight, and that similar capsules releasing 'high' doses of testosterone maintained spermatogenesis quantitatively up to and including step 7 of spermiogenesis.
CORRELATION BETWEEN THE EFFECTS OF HORMONES ON THE SYNTHESIS OF DNA IN EXPLANTS FROM INDUCED RAT MAMMARY TUMOURS AND THE GROWTH OF THE TUMOURS
Authors: LEWIS D. , HALLOWES R. C.
Published: December 2008

Explants from 32 mammary tumours induced in Sprague—Dawley rats by 9,10-dimethyl-1,2-benzanthracene (DMBA) were maintained in organ culture for up to 48 h. Insulin, corticosterone, prolactin, growth hormone and oestradiol were added to the culture medium in various combinations and their effects on the DNA synthesis of the explants was studied.

DNA synthesis was stimulated by insulin in explants from 30 out of the 32 tumours examined and this group of 30 responsive tumours could be further subdivided. Explants from 16 tumours showed a greater rate of DNA synthesis in medium containing insulin plus corticosterone plus prolactin than in medium containing insulin alone and this higher rate was decreased by oestradiol; this group is referred to as 'prolactin-responsive'. Explants from the remaining 14 tumours did not show a greater rate of DNA synthesis in medium that contained insulin plus corticosterone plus prolactin than in medium containing insulin alone and neither rate was decreased by oestradiol; this group is referred to as 'insulin-responsive'. Explants from two tumours were not stimulated by insulin and these tumours are referred to as 'non-responsive'. After oophorectomy or administration of ergocryptine to tumour-bearing rats, the prolactin-responsive tumours regressed whereas the non-responsive tumours continued to grow. Explants taken from prolactin-responsive tumours 2 weeks after either oophorectomy or administration of ergocryptine were still prolactin-responsive but those taken from insulin-responsive tumours 2 weeks after the same treatment were now also prolactin-responsive. The non-responsive tumours remained non-responsive.

The effects of hormones on the DNA synthesis in vitro of explants from growing DMBA-induced tumours were thus different from those on explants of mammary glands from virgin or pregnant Sprague—Dawley rats. It was concluded that it was possible to predict by organ culture techniques the response in vivo of growing mammary tumours to oophorectomy and ergocryptine administration.
CORTISOL SECRETION RATE, GLUCOSE ENTRY RATE AND THE MAMMARY UPTAKE OF CORTISOL AND GLUCOSE DURING PREGNANCY AND LACTATION IN DAIRY COWS
Authors: PATERSON J. Y. F. , LINZELL J. L.
Published: December 2008

Glucose entry rate was measured by primed infusion of [2-3H]glucose, and cortisol secretion rate by infusion of [1,2-3H2]cortisol, in two cows from 142 days before calving to day 287 of lactation. Mammary blood flow and the mammary uptake of glucose and cortisol were also measured.

In late pregnancy, cortisol secretion rate was 8·6 ± 3·17 (s.d.) μg/min and plasma cortisol concentration was 1·8 ± 0·52 μg/l. During parturition in one animal the secretion rate was 92 μg/min and plasma cortisol concentration was 15 μg/l. During lactation the secretion rate (26·4 ± 7·14 μg/min) and plasma cortisol concentration (5·6 ± 0·73 μg/l) were significantly greater than in dry cows. The mammary uptake of cortisol was 3 to 4% of the secretion rate in both dry and lactating cows.

Glucose entry rate was 5·77 ± 2·250 (s.d.) mg/min/kg0·75 in dry cows and there was no significant mammary uptake of glucose. During lactation the glucose entry increased to 9·45 ± 1·881 mg/min/kg0·75. Mammary uptake of glucose was 3·56 ± 1·949 mg/min/kg0·75. The non-mammary utilization of glucose, glucose entry less mammary uptake, was the same for dry and lactating cows.

There was a good correlation between glucose entry and milk yield, and between mammary uptake of glucose and milk yield. Since the mammary arterio-venous glucose concentration difference was relatively constant, it is suggested that the change in mammary blood flow may determine the change in glucose uptake and milk yield.
A NEW AND IMPROVED METHOD FOR THE SEPARATION OF FREE FROM PROTEIN-BOUND PROGESTERONE
Authors: BATRA S.
Published: December 2008

A method in which protein-bound and unbound progesterone are separated by filtering the sample through filters of cellulose esters is described. Because of a complete and almost instantaneous separation which is not influenced by pH, temperature and presence of cations or anions, the method lends itself for use in studies on progesterone binding in blood and in cytoplasmic fractions.
CONCENTRATIONS OF IMMUNOREACTIVE THYROTROPHIC HORMONE IN URINE OF NORMAL SUBJECTS, PATIENTS WITH THYROID DISORDERS AND HYPOPITUITARISM, AND AFTER INFUSION OF HUMAN THYROTROPHIC HORMONE
Authors: KUKU S. F. , HARSOULIS P. , YOUNG J. L. , FRASER T. R.
Published: December 2008

The urinary excretion of thyroid-stimulating hormone (TSH) has been measured by double antibody radioimmunoassay after concentration by dialysis followed by lyophilization. Among 30 normal subjects, the excretion was 5·6 ± 0·31 (s.e.m.) μu./h. No diurnal variation nor differences between sexes were discerned. In 14 primary hypothyroid subjects the urinary excretion was raised (P < 0·001) to 25·1 ± 3·3 μu./h. In 14 hyperthyroid and 7 hypopituitary subjects subnormal levels of 2·6 ± 0·2 and 2·5 ± 0·22 μu./h (P < 0·001) respectively, were found. Serum and urinary TSH concentrations were measured before, during and after an infusion of human pituitary TSH (MRC 70/9) in two subjects and showed a correlation.

Urinary TSH measurement is thus a good discriminant between normal and hyperthyroid or hypopituitary patients.
CONTROL OF UTERO-OVARIAN VENOUS PROSTAGLANDIN F DURING LABOUR IN THE SHEEP: ACUTE EFFECTS OF VAGINAL AND CERVICAL STIMULATION
Authors: FLINT A. P. F. , ANDERSON ANNE B. M. , PATTEN P. T. , TURNBULL A. C.
Published: December 2008

Simultaneous measurements of prostaglandin F, total unconjugated oestrogens and progesterone have been made in utero-ovarian venous or posterior vena caval plasma from pregnant ewes during parturition. In all cases, levels of oestrogens and prostaglandin F increased before delivery, after a decrease in the level of progesterone. In four out of six sheep, during both spontaneous and dexamethasone-induced labour, increases in the levels of oestrogens and prostaglandin F occurred in parallel. In the other two animals, levels of prostaglandin F increased before those of oestrogens. The increases in prostaglandin F consistently preceded any measurable increase in uterine activity, suggesting levels were not raised as a consequence of labour. Infusion of oestrogen to two dexamethasone-treated animals resulted in increased utero-ovarian venous prostaglandin F levels within 2–3 h. These findings support previous evidence indicating that levels of prostaglandin F may be controlled by oestrogen and progesterone. Manual examination of the cervix, with associated distension of the vagina, resulted in dramatic increases in the level of utero-ovarian venous prostaglandin F during the last 13 h of gestation, both in dexamethasone-induced labour and in labour of natural onset. Since expulsion of the foetus also results in vaginal distension, this finding raises the possibility that the very high levels of prostaglandin F observed at delivery may be caused by tactile stimulation of the vagina.
EFFECT OF OXIDATION ON BIOLOGICAL AND IMMUNOLOGICAL ACTIVITY OF PORCINE PARATHYROID HORMONE
Authors: O'RIORDAN J. L. H. , WOODHEAD J. S. , HENDY G. N. , PARSONS J. A. , ROBINSON C. J. , KEUTMANN H. T. , DAWSON B. F. , POTTS J. T.
Published: December 2008

The presence of a single methionine in porcine parathyroid hormone, at position 8, permitted assessment of the role of this residue separate from the second methionine residue found at position 18 of bovine and human parathyroid hormones. Oxidation of the solitary methionine of porcine parathyroid hormone to the sulphoxide destroyed biological activity, but this was restored by subsequent reduction with cysteine. Oxidation of the hormone did not, however, affect its immunological activity; therefore, oxidation of the hormone may bring about dissociation of biological and immunological activity.
THYROID ACTIVITY AND OXIDATIVE METABOLISM IN A SPECIES OF GECKO (HEMIDACTYLUS FLAVIVIRIDIS RÜPPELL) IN RELATION TO SEX HORMONES
Authors: CHANDOLA ASHA , KUMAR D. SURESH , THAPLIYAL J. P.
Published: December 2008

Orchidectomy in Hemidactylus flaviviridis led to significant reduction of thyroidal 131I uptake, thyroidal content of thyroxine, plasma protein-bound iodine and oxygen consumption of isolated liver and skeletal muscle (at 30 °C). Administration of testosterone to orchidectomized lizards restored these parameters to normal levels. Dependence of thyroid function and oxidative metabolism on male hormone may be a general feature in reptiles. This hormone may, therefore, be of greater physiological importance in these animals than in other vertebrates. Since reptiles occupy a crucial phylogenetic position in the animal kingdom these findings are important from the point of view of evolution of the functional aspects of hormones in vertebrates.

The results also show that thyroid function is inhibited by oestrogen(s) in this lizard. This may be an adaptive compensatory measure to control (through effects of the thyroid on metabolic activities) the extra expenditure of energy usually associated with such energy-consuming functions as ovulation and egg-laying.
THE SITE OF SECRETION OF ANDROSTENEDIONE IN NON-PREGNANT WOMEN
Authors: BAIRD D. T. , BURGER P. E. , HEAVON-JONES G. D. , SCARAMUZZI R. J.
Published: December 2008

The site of secretion of androstenedione in women was investigated by measuring the concentration of androstenedione in peripheral and ovarian venous plasma by radioimmunoassay at different stages of the menstrual cycle. The concentration in peripheral plasma rose from 1·45 ± 0·11 (s.e.m.) ng/ml on day 1 to a peak on the 7 days around mid-cycle (2·29 ± 0·08) before declining gradually during the luteal phase. The concentration of androstenedione in plasma draining ovaries containing the pre-ovulatory follicle or a corpus luteum (33·2 ± 9·0) was significantly higher than in plasma draining the contralateral ovary (10·1 ± 1·6, P < 0·001). In women in whom ovulation was induced with gonadotrophins the concentration of androstenedione in peripheral plasma rose from 1·42 ± 0·21 before treatment to reach maximum levels (2·5–4·5 ng/ml) in the luteal phase. There was a significant (P < 0·001) correlation between the concentration of androstenedione and oestradiol-17β in peripheral (r = 0·50) and ovarian (r = 0·79) venous plasma. These findings indicate that all three cellular compartments in the ovary secrete significant amounts of androstenedione in women during their reproductive life.
OESTROGEN AND THE CONTROL OF GONADOTROPHIN SECRETION IN THE IMMATURE RAT
Authors: DÖCKE F. , DÖRNER G.
Published: December 2008

Experiments were performed in female Wistar rats on the mode of action of oestrogen in affecting gonadotrophin secretion during infancy. Using an improved implantation method, former findings on a hypophysial site of oestrogen action in the Hohlweg effect were confirmed. The sensitivity to the ovulation-inducing effect of oestradiol benzoate (OB) increased as the rats approached the age of natural puberty. The first spontaneous ovulation could be suppressed by intrahypophysial, but not by intrahypothalamic, progesterone implants.

A single s.c. injection or intracranial administration of OB at 25 or 26 days of age, although leading to premature vaginal opening (VO) and, in some of the animals, to one ovulation, did not induce true precocious puberty. To accelerate the onset of puberty, 0·05 μg OB/100 g body wt had to be injected daily from 5 days of age to VO, or from day 5 to day 10 and, additionally, from day 26 to VO. After long-term oestrogen treatment, the gonadotrophin-inhibiting effect of OB implanted into the middle hypothalamus from 26 to 34 days of age was significantly reduced in comparison with untreated control rats. A final experiment demonstrated that the first ovarian cycle was not prolonged after neonatal ovariectomy and implantation of ovaries at 24, 28 or 32 days of age. The results indicate that similar neurohormonal mechanisms are operational at the first pubertal and at later cyclic ovulations. They also indicate that the maturation of the gonadotrophin-controlling mechanisms continues during infancy in the absence of ovarian steroids. It can be accelerated in Wistar rats by long-term, but not by short-term prepubertal oestrogen treatment.
CIRCADIAN PERIODICITY AND STRESS RESPONSIVENESS OF THE PITUITARY–ADRENAL SYSTEM OF RATS AFTER CENTRAL ADMINISTRATION OF 6-HYDROXYDOPAMINE
Authors: KAPLANSKI J. , VAN DELFT A. M. L. , NYAKAS C. , STOOF J. C. , SMELIK P. G.
Published: December 2008

Injection of 250 μg 6-hydroxydopamine (6-OHDA) into the lateral ventricle of adult male and female rats resulted 1 week later in: (1) a lowered brain content of noradrenaline to 20% and dopamine to 40–50% that of control levels but no change in brain serotonin content; (2) a slight reduction in male and no change in female body weight; (3) no change in adrenal weight; (4) minor or no changes in diurnal pituitary–adrenal periodicity or in the responsiveness of this system to ether stress, laparotomy or exposure to a strange environment and handling. Dexamethasone blockade of the diurnal rise in adrenocortical activity was also unchanged.

Intracerebral administration of 200 μg 6-OHDA to newborn male and female rats in three sequential doses of 40, 60 and 100 μg, resulted at 12 weeks of age in (1) a lowered brain content of noradrenaline and dopamine to 10% that of control levels but no change in brain serotonin; (2) a 30% decrease in body weight; (3) no change in adrenal weight; (4) minor or no changes in pituitary–adrenal periodicity nor in the responsiveness to ether stress and exposure to a strange environment and handling.

When minor changes after 6-OHDA treatment of adult or neonatal rats were found, they always pointed to a stimulatory function of brain catecholamines in pituitary–adrenal activity. It is concluded however that a severe and chronic depletion of brain catecholaminergic systems has no important consequences for the normal functioning of the pituitary–adrenal system.
PLASMA CONCENTRATIONS OF CORTISOL IN HYPOPHYSECTOMIZED AND SODIUM CHLORIDE-ADAPTED GOLDFISH (CARASSIUS AURATUS L.)
Authors: PORTHÉ-NIBELLE JACQUELINE , LAHLOU BRAHIM
Published: December 2008

Plasma cortisol concentrations, measured by competitive protein-binding, were examined in intact and hypophysectomized goldfish (Carassius auratus L.) adapted to fresh water or to 210 mm-sodium chloride solutions. The mean plasma cortisol concentration of freshwater-adapted fish (6·6 ± 1·8 (s.e.m.) μg/100 ml plasma) increased after stress and intraperitoneal injections of mammalian corticotrophin. Hypophysectomy resulted in a reduction in plasma cortisol concentration to about 2 μg/100 ml plasma.

Transfer of fish to sodium chloride solutions caused rapid, but transitory increases in the plasma cortisol concentrations in intact, but not in hypophysectomized fish. After 3 days in the sodium chloride solution the cortisol levels were similar to those of control fish kept in fresh water. The plasma concentrations of this corticosteroid in goldfish appear to be unrelated to external salinity, although a 'mineralocorticoid' action of the hormone cannot be excluded.
CHANGES IN THE CONCENTRATIONS OF CORTISOL AND CORTICOSTERONE IN THE PLASMA AND ADRENAL GLANDS OF THE GUINEA-PIG FROM BIRTH TO WEANING
Authors: DALLE M. , DELOST P.
Published: December 2008

Concentrations of cortisol and corticosterone in the plasma and adrenal glands of male and female guinea-pigs were estimated throughout the first postnatal day and thereafter at intervals up to 3 weeks of age. In the guinea-pig, the basal level of cortisol secretion is established more slowly than in other species. The concentration of plasma cortisol is very high at birth, with a marked fall between days 1 and 10 post partum and then a steady level from day 10 to 20, the time of weaning. At day 10 the values for plasma cortisol and corticosterone approach the lower ones found in the adult. There were peaks in the amounts of corticosteroids found in the adrenal gland at 50 h, 4 and 7 days and these may have been due to increased hormonal synthesis between days 2 and 8.
STEROIDOGENESIS IN VITRO BY THE OVARIAN TISSUE OF THE DOMESTIC FOWL (GALLUS DOMESTICUS)
Authors: NAKAMURA TAKAO , TANABE YUICHI , KATUKAWA HIDEO
Published: December 2008

Ovaries excised from 5- and 7-month-old laying hens were homogenized. The homogenates were incubated separately with 4-14C-labelled pregnenolone, progesterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone, oestrone and oestradiol, and [7-3H]17αhydroxypregnenolone in the presence of NAD+ or NADPH under aerobic conditions. The homogenates synthesized progesterone, 17αhydroxyprogesterone, 17α-hydroxypregnenolone, dehydroepiandrosterone, androstenedione, testosterone, pregnanedione, 17α-hydroxy-5β-pregnane3,20-dione, 5β-androstane-3,17-dione, 19-hydroxyandrostenedione, 19hydroxytestosterone, oestrone, oestradiol and other minor metabolites. However, the rates for the conversion of androstenedione to oestrone and that of testosterone to oestradiol were low, and after 120 min incubation, the yields were 3·0 and 1·2%, respectively. The results indicate possible involvement of metabolic pathways both from Δ5-C21 steroid to Δ4-C21 steroid and from Δ5-C21 steroid to Δ5-C19 steroid in the formation of androgen by the ovary of the domestic fowl.
EFFECT OF OESTRADIOL-17β AND PROGESTERONE ON THE METABOLISM OF TESTOSTERONE BY HUMAN PROSTATIC TISSUE
Authors: JENKINS J. S. , McCAFFERY V. M.
Published: December 2008

The metabolism of testosterone in vitro by normal benign hyperplastic and carcinomatous prostatic tissues has been compared. 5α-Dihydrotestosterone was the predominant metabolite followed by 3α- and 3β-androstanediol. No difference in the pattern of metabolism, either quantitatively or qualitatively, was found in normal, benign hyperplastic and welldifferentiated carcinomatous prostatic tissue. In poorly differentiated carcinomatous tissue there was less formation of all 5α-reduced metabolites. Treatment of patients with carcinomata with diethylstilboestrol resulted in greatly decreased activity of prostatic 5α-reductase with a considerable proportional increase in 17β-dehydrogenase activity. The addition of oestradiol-17β or stilboestrol in vitro also inhibited the formation of 5αdihydrotestosterone and androstanediols by all types of prostatic tissue, but only when high concentrations of oestrogen were used and there was no increase in 17β-dehydrogenase under these conditions. In contrast, progesterone was a much more effective inhibitor of 5α-reductase in vitro than was oestrogen.
BINDING OF HUMAN CHORIONIC GONADOTROPHIN BY RAT TESTIS: EFFECT OF SEXUAL MATURATION, CRYPTORCHIDISM AND HYPOPHYSECTOMY
Authors: FROWEIN JOACHIM , ENGEL WOLFGANG
Published: December 2008

The specific binding of 125I-labelled human chorionic gonadotrophin (HCG) by rat testicular homogenate as compared with isolated Leydig cells differs with respect to total binding capacity but not to the dissociation constant (KD) as revealed by Scatchard analysis. The maximal binding capacity for [125I]HCG of crude testicular homogenate was 95 ng/g rat testis. Hypophysectomy causes a decline in binding capacity within the first three days but on the 20th and 30th day after hypophysectomy the relative binding capacity no longer differs from that of controls. Binding capacity is enhanced in cryptorchid testes relative to normal, and increases during sexual maturation to a peak shortly before puberty.
ADRENOCORTICOTROPHIN AND THE DEVELOPMENT OF INSULIN SECRETION IN THE RABBIT FOETUS
Authors: JACK P. M. B. , MILNER R. D. G.
Published: December 2008

Foetal rabbits were injected with adrenocorticotrophin (ACTH), decapitated, or decapitated and injected simultaneously with ACTH or cortisol in utero on day 24 of gestation. The foetuses were killed after Caesarian section on day 29, and blood was collected for measurement of plasma insulin concentration and pancreatic tissue was obtained for incubation in physiological buffer. Insulin release from the pancreatic tissue of decapitated foetuses was significantly greater than that from the pancreas of control litter-mates when incubated in media containing 3·3 mm-glucose, 16·5 mm-glucose or 16·5 mm-glucose plus 5 μg glucagon/ml, but was similar when the incubation medium contained 3·3 or 16·5 mm-glucose plus 1 mm-theophylline or 3·3 mm-glucose plus 60 mm-potassium. The pancreata of decapitated or intact foetuses injected with ACTH did not differ significantly from control foetuses in terms of insulin release in response to glucose in vitro. The plasma insulin concentration of decapitated foetuses and decapitated foetuses injected with ACTH was raised, whereas that of intact foetuses injected with ACTH was similar to that of the control foetuses. Cortisol injection at the time of decapitation resulted in a high rate of foetal mortality.

The results indicate that foetal ACTH or foetal adrenocortical secretion influences the normal development of glucose-mediated insulin secretion in the rabbit and that exogenous ACTH corrects the effect of decapitation on β cell function in vitro but not on plasma insulin concentration.
EPISODIC RELEASE OF LUTEINIZING HORMONE IN THE DOMESTIC FOWL
Authors: WILSON SUSAN C. , SHARP P. J.
Published: December 2008

Plasma luteinizing hormone (LH) levels were measured by radioimmunoassay in serial samples taken from intact adult cockerels, gonadectomized fowl of both sexes and laying hens. By sampling at 30 and 10 min intervals, it was shown that in cockerels LH is released episodically. Each secretory episode lasted 90–120 min and was characterized by a 100–200% rise in LH levels over a period of 10–15 min followed by a more gradual, exponential decline. Mean plasma LH levels were found to be depressed in cockerels as a result of the handling associated with taking blood samples; in cases where LH levels were most depressed, an episodic pattern of secretion could not be demonstrated.

In the gonadectomized fowl, an episodic pattern of LH secretion was shown when blood samples were taken at 10 or 5 min intervals. During each secretory episode, which lasted 20–45 min, LH levels rose by 20–60%. It is suggested that the increase in mean plasma LH levels in gonadectomized fowl (30–77 ng/ml) over those in cockerels (7–16 ng/ml) is related to an increase in the frequency of the episodic release of the hormone. Episodic discharges of LH could not be demonstrated in laying hens. In these birds the mean LH levels are low (1·5–2·4 ng/ml) and consequently may be maintained by secretory episodes which are of too low an amplitude to be detectable.
EFFECTS OF TESTOSTERONE AND PROLACTIN OR GROWTH HORMONE ON THE ACCESSORY SEX ORGANS OF CASTRATED MICE
Authors: KEENAN E. J. , THOMAS J. A.
Published: December 2008

In 5-day experiments, neither bovine prolactin (300 or 600 i.u./kg) nor ovine growth hormone (25 i.u./kg) alone significantly enhanced accessory sex organ weights in the castrated mouse. Seminal vesicle weights, and to a lesser extent anterior prostate gland weights, were augmented by the simultaneous injection of testosterone (1·5 mg/kg) daily plus prolactin or growth hormone. The effect was greater than that produced by testosterone alone.

The levels of fructose in accessory sex organs used to indicate androgenic activity were similar in castrated mice receiving testosterone alone or in combination with prolactin or growth hormone. Prolactin alone did not influence uptake of [3H]testosterone by the seminal vesicles or anterior prostate gland over a 5 min period in vivo.
EFFECTS OF CASTRATION, AND TESTOSTERONE IN VITRO, ON THE HYPOTHALAMIC SYNTHESIS OF DIFFERENT PEPTIDE FRACTIONS
Authors: MOGUILEVSKY J. A. , ENERO M. A. , SZWARCFARB B. , DOSORETZ D.
Published: December 2008

The incorporation of [3H]tyrosine ([3H]tyr) into different hypothalamic peptide fractions isolated from normal and castrated rats on a Sephadex G-25 column has been studied in vitro. Luteinizing hormone releasing factor (LH-RF) activity was determined in the different fractions by measuring their ability to elicit release of radioimmunoassayable luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in ovariectomized rats treated with oestrogen and progesterone.

For further purification, the fraction with LH-RF activity was applied to a CM-Sephadex G-25 column eluted with a gradient of ammonium acetate. The large radioactive peptides emerged from the Sephadex G-25 column in fraction S-1, while the small peptides with LH-RF activity were eluted in fraction S-2. Gonadectomy significantly increased the incorporation of [3H]tyr into the peptides of fractions S-2. Only in the purified fraction with LH-RF activity was the radioactivity incorporated higher in gonadectomized than in normal rats. The enhanced incorporation in fraction CM-3 observed after castration implies an increase in the hypothalamic synthesis of peptides with LH-RF activity. The addition of testosterone (2 μg/ml) to the incubation medium of hypothalamus from gonadectomized rats, corrected these modifications.

Gonadectomy decreased the incorporation of tyrosine into the large peptides, and incubation with testosterone corrected this change.

The modifications in the incorporation of [3H]tyr into the large and small peptides produced by castration appear to indicate that gonadectomy, as well as stimulating the production of LH-RF, enhances the synthesis of other hypothalamic peptides while inhibiting the synthesis of proteins. On the other hand an increase in the breakdown of large peptides into small peptides cannot be excluded.