bluuebunny/crossref_metadata_2025 huggingface dataset:
SIMULTANEOUS RADIOIMMUNOASSAY OF LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE
Authors: ELLIS M. J. , DONALD R. A. , LIVESEY J. H.
Published: December 2008

The Medical Unit, The Princess Margaret Hospital, Christchurch 2, New Zealand

(Revised manuscript received 21 August 1978)

The frequent clinical and research requirement for measurement of both plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) has prompted the development of a simultaneous radioimmunoassay for these two hormones. The considerable advantages of a simultaneous method include an economy of plasma volume, assay reagents, test-tubes and, more importantly, the time required for radioactive counting and performance of the assay by technical staff. The latter two factors comprise a significant proportion of radioimmunoassay operating costs.

This report describes a simultaneous radioimmunoassay based on the use of 131I-labelled FSH, 125I-labelled LH, anti-FSH serum M93 6873 (a generous gift from Professor W. R. Butt, Birmingham), anti-human chorionic gonadotrophin (HCG) serum for LH measurement (Donald, 1972) and donkey anti-rabbit precipitating serum (Wellcome Reagents, U.K.) for separation of antibody-bound and free hormones. Pituitary gonadotrophin standard (LER 907)
COMPARISON OF THE STIMULATORY EFFECTS OF OVINE, PORCINE AND HUMAN FOLLICLE-STIMULATING HORMONE AND OF OVINE AND HUMAN LUTEINIZING HORMONE ON THE ACCUMULATION OF CYCLIC AMP BY PORCINE GRANULOSA CELLS
Authors: LINDSEY ADA M. , CHANNING CORNELIA P.
Published: December 2008

The effects of ovine, porcine and human FSH, and ovine and human LH on the accumulation of cyclic AMP by porcine granulosa cells obtained from follicles at various stages of maturation were investigated. During incubation periods of 15 min, 10 μg ovine FSH pretreated with antiserum to LH or 10 μg human FSH resulted in an 11- to 18-fold, five-to ninefold, and less than a twofold increase in intracellular accumulation of cyclic AMP by granulosa cells from small (1–2 mm), medium (3–5 mm) and large (6–12 mm) follicles respectively. Similar patterns of response occurred with addition of porcine FSH. After incubation for 30 and 60 min with ovine, porcine or human FSH, significant accumulation of cyclic AMP in the incubation medium occurred with cells obtained from small and medium-sized follicles. After 60 min of incubation with FSH the accumulation of cyclic AMP in the incubation medium exceeded the intracellular cyclic AMP levels in granulosa cells from small and medium-sized follicles.

During incubation periods of 15 min, 1·0 μg ovine LH resulted in less than a twofold, a fourfold and greater than a tenfold increase in intracellular accumulation of cyclic AMP by granulosa cells from small, medium and large follicles respectively. Addition of human LH brought about a similar response. Incubation periods of 30 and 60 min with 1·0 μg ovine or human LH resulted in significant accumulation of cyclic AMP in the incubation medium by granulosa cells from large follicles; cyclic AMP content in the incubation medium was greater after 60 min compared with 30 min of incubation.

It was concluded that ovine FSH pretreated with an antiserum to LH had similar effects on cyclic AMP levels as did purified human and porcine FSH, and that the stimulatory effects of the less pure ovine FSH were probably not due to an impurity in the FSH preparation. Porcine granulosa cells obtained from small follicles should be suitable as an in-vitro FSH bioassay while granulosa cells obtained from large follicles should be suitable as an in-vitro LH bioassay.
EVIDENCE TO SUGGEST THAT RAT GROWTH HORMONE IS MODIFIED WHEN SECRETED BY THE PITUITARY GLAND
Authors: VODIAN M. A. , NICOLL C. S.
Published: December 2008

The relationships were examined between the concentrations of GH determined by bioassay (rat tibia test) and radioimmunoassay in homogenates of rat adenohypophysial tissue and in the incubation medium in which the tissue had been maintained. Adenohypophyses from young male rats were incubated in Medium 199 with or without a putative synthetic GH-releasing factor (GRF) to achieve a dynamic state of GH secretion, but the GRF did not consistently stimulate the release of GH as measured by either bioassay or radioimmunoassay. Both assays gave closely similar values for the concentration of GH in homogenates of the adenohypophyses of undisturbed rats. When the two assays were used to measure the concentrations of GH in incubated pituitary tissue, the values showed no correlation, although the concentrations of GH in the incubation medium were again highly correlated. However, the bioassay: radioimmunoassay ratio for the secreted hormone [2·14 ± 0·09 (s.e.m.)] was significantly higher than that for the intrapituitary form from the unincubated gland (0·93 ± 0·06).

By radioimmunoassay, secreted rat GH was found to be less stable than purified rat GH when the two forms were incubated in vitro with slices of various rat tissues. Similarly, the rate of clearance of secreted rat GH from the plasma of hypophysectomized rats, as determined by radioimmunoassay, was much faster than that of the purified GH. The biological activity of purified bovine GH was blocked by aprotinin, an inhibitor of proteolysis, but the drug had no inhibitory effect on the bioactivity of rat GH secreted into the incubation medium.

Overall, these results indicate that secreted rat GH has properties intermediate between those of the intrapituitary form and the form found in the circulation.
CHARACTERIZATION OF THE SPECIFIC BINDING OF PROLACTIN TO BINDING SITES IN THE SEMINAL VESICLE OF THE RAT
Authors: BARKEY R. J. , SHANI J. , AMIT T. , BARZILAI D.
Published: December 2008

The binding of ovine prolactin to the seminal vesicles of the rat has been characterized and found to be a saturable process, dependent upon time, temperature, protein concentration of the seminal vesicle and divalent ions. Its specificity was similar to that reported for prolactin binding to other organ preparations. Time and temperature studies of the specific binding revealed that equilibrium was reached after 16 h at 5 °C or 4 h at 19 °C. Non-specific binding was also dependent on time and temperature. This parameter has been reported to comprise up to 70% of the total binding to various organ-binding sites, but it fell to below 20% after 48 h at 19 °C, thus demonstrating the high degree of specificity required of target organ receptors.

From degradation studies it was evident that no damage occurred to the free hormone during incubation for up to 70 h at 5 °C or 16 h at 19 °C. However, there seems to be a difference in the susceptibility of bound and free ovine prolactin to damage during incubation: after 40 h at 19 °C the hormone in the supernatant fraction had lost 85% of its binding ability, whereas a high level of specific binding was evident in the pellet. A Scatchard plot of competitive binding studies revealed two classes of binding sites, of which the high-affinity, low-capacity site was similar to that reported previously and consistent with a physiological receptor for prolactin in the seminal vesicle of the rat.
INTERACTION OF OVARIAN TISSUES IN THE CONTROL OF FOLLICULAR STEROIDOGENESIS IN CULTURE
Authors: MOOR R. M. , WALTERS D. E.
Published: December 2008

The interaction between developing antral follicles and other ovarian tissues in sheep was examined in vitro. Small follicles (2·0–2·9 mm in diameter) were co-cultured with a single ovarian component for 48 h, then separated and cultured singly for a further 72 h during which time changes in follicular steroidogenesis and structure were measured.

Control follicles, cultured together for 48 h before separation, had a mean total daily steroid output during the 72 h test period of 180·4 ± 12·6 (s.e.m.) pmol mg tissue−1 24 h−1; oestrogen (61·7 ± 8·2 pmol mg−1 24 h−1) and testosterone (84·4 ± 9·2 pmol mg−1 24 h−1) accounted for 81% of the steroid secreted by control follicles.

The presence of stromal tissue during co-culture depressed (P < 0·01) the subsequent output of total steroid by 22%, oestrogen by 81% and testosterone by 38%; progesterone output was, however, over twice that of the controls. There were no distinctive structural differences between follicles in the control and stromal groups.

Luteal tissue enhanced (P < 0·01) the output of total steroid by 51%, testosterone by 55% and progesterone by 242%; oestrogen output was similar to that in the controls. Follicles co-cultured with luteal tissue were characterized by extensive hypertrophy of the theca interna.

Developing follicles co-cultured with large non-atretic follicles had a similar total steroid output, a slightly higher oestrogen output and more thecal hypertrophy than the controls. Follicles co-cultured with large atretic follicles differed from controls only with respect to their greater capacity to synthesize progesterone.
MAMMARY GROWTH DURING PREGNANCY IN HYPOPHYSECTOMIZED OR BROMOCRIPTINE-TREATED GOATS
Authors: BUTTLE H. L. , COWIE A. T. , JONES E. A. , TURVEY A.
Published: December 2008

Mammogenesis in primiparous hypophysectomized goats has been assessed between days 60 and 120 of gestation and compared with that found in untreated goats and goats treated with 5 mg bromocriptine/day. There were fivefold increases in the weight of lobulo-alveolar tissue in the hypophysectomized and bromocriptine-treated goats and a tenfold increase in the untreated goats. Histological examination of the mammary glands at 120 days showed normal structure, and determinations of lactose, lactose synthetase, cytosol enzymes, protein, DNA and RNA indicated qualitatively normal initiation of milk synthetic capabilities in both the hypophysectomized and bromocriptine-treated goats. Bromocriptine treatment lowered the plasma concentration of placental lactogen as well as that of prolactin.

The results indicate that placental lactogen has important mammogenic effects during pregnancy.
REVERSAL OF PROGESTERONE INHIBITION OF SEXUAL BEHAVIOUR IN OVARIECTOMIZED RATS BY HIGH DOSES OF PROGESTERONE
Authors: HANSEN S. , SÖDERSTEN P.
Published: December 2008

Considerably less progesterone was needed to facilitate than was required to inhibit sexual receptivity induced by oestradiol benzoate (OB) and progesterone in the ovariectomized rat. Inhibition of sexual receptivity occurred if progesterone was given at the time of OB treatment (concurrent inhibition). If progesterone was given 42 h after the OB treatment it first acted to facilitate the behaviour and then to inhibit the response to renewed progesterone treatment 24 h later (sequential inhibition). Both concurrent and sequential inhibition of sexual receptivity by progesterone could be reversed by increasing the dose of progesterone before behavioural testing. Sexual receptivity could be induced in the pseudopregnant rat by using a low dose of OB (2 μg) in combination with a very high dose of progesterone (50 mg). Sexual receptivity induced in ovariectomized rats by injection of a single large dose of OB was unaffected by progesterone treatment in both the concurrent and sequential paradigm. Concurrent and sequential inhibition of sexual behaviour by antioestrogen (nitromophene monocitrate, CI-628) treatment could not be reversed by increasing the dose of progesterone before testing. The behavioural response to OB treatment in combination with progesterone and OB treatment alone was markedly inhibited by CI-628 treatment. It is suggested that prior treatment with progesterone raises the threshold of the behavioural response to subsequent progesterone treatment. It is also suggested that the inhibitory effect of progesterone on sexual behaviour cannot only be accounted for by the previously suggested antioestrogenic effect of progesterone.
INDUCTION OF SEXUAL RECEPTIVITY BY OESTRADIOL BENZOATE IN CYCLIC FEMALE RATS: INFLUENCE OF OVARIAN SECRETIONS BEFORE INJECTION OF OESTRADIOL BENZOATE
Authors: SÖDERSTEN P. , HANSEN S.
Published: December 2008

The ability of cyclic female rats to show sexual receptivity 24 h after an injection of 2 μg oestradiol benzoate (OB) was lost 24 h after ovariectomy. Exposure of cyclic rats to anti-oestrogen (nitromophene monocitrate) implants 24 h before ovariectomy and OB treatment prevented the latter from inducing sexual receptivity within 24 h of administration. Treatment of ovariectomized rats with constant release implants filled with an oil solution of 15 μg oestradiol/ml had no behavioural effect in itself, but prepared the rats to show lordosis 24 h after administration of OB. Progesterone treatment (4 mg) induced sexual behaviour in cyclic rats on days other than that of the oestrous cycle when the rats are normally receptive. Evidence is presented that a lower level of oestradiol stimulation than that present during pro-oestrus was needed for the induction of sexual receptivity in ovariectomized rats. It is suggested that the low basal level of oestradiol which was present throughout the oestrous cycle was necessary for the induction of sexual receptivity and that an increase in oestradiol stimulation served to increase the behavioural sensitivity to progesterone.
DEVELOPMENT AND APPLICATION OF HOMOLOGOUS RADIOIMMUNOASSAYS FOR PORCINE GONADOTROPHINS
Authors: VANDALEM J. L. , BODART CH. , PIRENS G. , CLOSSET J. , HENNEN G.
Published: December 2008

Antisera were raised against highly purified preparations of porcine luteinizing hormone (pLH) and follicle-stimulating hormone (pFSH). Highly specific and sensitive radioimmunoassay systems were developed.

The antisera to LH and FSH were used at working dilutions of 1: 500 000 and 1: 200 000 respectively and the sensitivities of the assays were 0·1 ng LH/ml serum (3 × 10−12 mol/l) and 0·5 ng FSH/ml serum (1·5 × 10−11 mol/l). The LH and FSH preparations used as standards were 1·2 and 81 times as potent as NIH-LH-S15 and NIH-FSH-P1 respectively. Both assays were validated and adapted for the measurement of the gonadotrophin content of porcine serum.

The concentrations of LH and FSH in blood were measured simultaneously in prepubertal sows throughout a 24 h period, in adult sows during the oestrous cycle and in both prepubertal and adult animals after treatment with LH releasing hormone.
ADRENOCORTICOTROPHIN-RELATED PEPTIDES IN ADULT AND FOETAL SHEEP PITUITARY GLANDS
Authors: SILMAN R. E. , HOLLAND DIANE , CHARD T. , LOWRY P. J. , HOPE J. , REES LESLEY H. , THOMAS A. , NATHANIELSZ P.
Published: December 2008

Differences in foetal and adult adrenal function may be due to qualitative as well as quantitative changes in the pituitary corticotrophic stimulus. Pituitary glands from adult and foetal sheep were freshly dissected and stored at −70 °C until extracted at pH 1·5. The extracts were subjected to chromatography on Sephadex G-100 superfine and fractions were assayed by multiple radioimmunoassays directed against the NH2- and CO2H-terminal sequences of ACTH and lipotrophin (LPH). Peaks corresponding to β-melanocyte-stimulating hormone (β-MSH), β-LPH, γ-LPH, β-endorphin and ACTH were identified, with little or no evidence for the presence of α-MSH and corticotrophin-like intermediate lobe peptide. Three peaks of large molecular weight material, A. B and C, were identified and their relative proportions shown to be considerably greater in the foetus than in the adult. The immunoassay profile of peaks A and B suggested that they were 'stem hormones' which could give rise to a family of biologically active peptides. Since the 'family tree' which they engender varies according to the stage of development, it is proposed that the changes in the 'trophic family' may explain the different adrenal responses of the foetal and adult sheep.
PLASMA CONCENTRATIONS OF OVARIAN HORMONES DURING THE OESTROUS CYCLE OF THE SHEEP AND COW
Authors: HERRIMAN I. D. , HARWOOD D. J. , MALLINSON C. B. , HEITZMAN R. J.
Published: December 2008

Measurements were made of the plasma concentrations of testosterone, progesterone and oestradiol-17β during the oestrous cycle of the ewe, and of the plasma concentrations of testosterone and progesterone during the oestrous cycle of the heifer. The maximum concentration of progesterone in the heifer was nearly twice that in the ewe. The maximum concentration of testosterone was similar in both species and occurred at the onset of luteolysis; in the ewe the peak concentration of 19·5 pg/ml plasma was significantly greater (P < 0·05) than the concentrations of testosterone measured during the remainder of the oestrous cycle.
ANDROGEN RECEPTORS IN THE RAT BRAIN, ANTERIOR PITUITARY GLAND AND VENTRAL PROSTATE GLAND: EFFECTS OF ORCHIDECTOMY AND AGEING
Authors: GREENSTEIN B. D.
Published: December 2008

Available high-affinity binding sites for 5α-dihydrotestosterone (DHT) were measured in cytosols obtained from the amygdala, hypothalamus, anterior pituitary gland and ventral prostate gland of 12-week-old rats at various times after orchidectomy, and in the corresponding tissues of 18-month-old male rats. It is suggested that the lower affinity of the DHT binding reaction in brain and ventral prostatic cytosols after orchidectomy or ageing respectively, may explain, at least in part, the changes in the responsiveness of the tissues to androgens.
ULTRADIAN AND CIRCADIAN RHYTHMS IN THE PLASMA CONCENTRATION OF CORTISOL IN SHEEP
Authors: FULKERSON W. J. , TANG B. Y.
Published: December 2008

Three Merino ewes, adapted for about 3 weeks to their environment, were bled at 10 min intervals through a jugular venous cannula. Radioimmunoassay of plasma samples for cortisol revealed marked diurnal variations with peak levels just after midnight and lowest values in the afternoon. This rhythm appeared to result from a changing amplitude associated with a distinct ultradian rhythm (frequency 0·8–1·2 cycles/h) in the plasma level of cortisol. Calculation of the daily rate of secretion of cortisol from the hormone profiles gave a mean value of 8·49 mg. Arguments are put forward in favour of this method for obtaining the true rate of secretion of cortisol.
EFFECT OF CARBENOXOLONE ON THE CONCENTRATIONS OF ALDOSTERONE IN RAT PLASMA AND KIDNEY
Authors: HUMPHREY M. J. , LINDUP W. E. , CHAKRABORTY J. , PARKE D. V.
Published: December 2008

The renal subcellular distribution of various subcutaneous doses (10−10–10−8 mol) of [3H]aldosterone has been investigated in adrenalectomized rats pretreated with carbenoxolone.

Carbenoxolone increased the concentration of plasma [3H]aldosterone, but the uptake of [3H]aldosterone into the kidney nuclear and cytosol fractions was decreased. Pretreatment of rats with carbenoxolone at low doses of aldosterone (0·4 × 10−10 and 1·5 × 10−10 mol) decreased both the amount of [3H]aldosterone bound to the 50% (NH4)2SO4 precipitate, and that present in the supernatant fraction, of a Tris–CaCl2 extract of the kidney nuclear fraction. Carbenoxolone also decreased the rate of biliary excretion of metabolites of aldosterone.

When [3H]aldosterone and carbenoxolone were incubated with Tris–CaCl2 extracts of a kidney nuclear fraction in vitro, the carbenoxolone did not decrease the [3H]aldosterone bound to the 50% (NH4)2SO4 precipitate, although the [3H]aldosterone bound to the 50% (NH4)2SO4 supernatant was significantly decreased by carbenoxolone at concentrations known to occur in the kidney in vivo.

These results indicate that displacement of aldosterone from binding sites, with a concomitant potential increase in the amount of hormone available to specific receptors may be part of the mechanism by which carbenoxolone potentiates aldosterone action in toad skin in vitro. However, in rat kidney, such a mechanism is unlikely to play a significant role in the manifestation by carbenoxolone of aldosterone-like effects. Data are presented to indicate that carbenoxolone may affect the normal distribution and metabolism of aldosterone, and it is possible that potentiation of aldosterone action may involve receptors in other tissues, such as the gastrointestinal tract which is the major site of action of carbenoxolone.
SYNTHESIS OF DNA AND LECITHIN IN TISSUE CULTURE AND OESTROGEN RECEPTOR ACTIVITY IN RAT MAMMARY TUMOURS DEPENDENT ON AND INDEPENDENT OF THE OVARY
Authors: SCOTT ANNE-MARIE , MURPHY SUSAN , HAWKINS R. A.
Published: December 2008

Dimethylbenz(a)anthracene (DMBA)-induced and transplanted rat mammary tumours (2 lines) were examined for oestrogen receptor activity, and for sensitivity to hormones in vivo (by ovariectomy) and in vitro (by tissue culture). In vivo, the growth of all tumours induced by the administration of DMBA in random-bred Sprague–Dawley rats was found to be dependent on the ovary, whilst in all transplanted tumours (12 TG-3 and six TG-5 lines), maintained in an inbred strain of Sprague–Dawley rats, growth was found to be independent of the ovary. In vitro, the capacity for DNA synthesis in DMBA-induced tumours was better maintained after 24 h when insulin (10 μg/ml) and corticosterone (5 μg/ml) or insulin, corticosterone and prolactin (each 5 μg/ml) were present in the medium (five out of 12 and eight out of 11 tumours respectively); no effect of hormones in the media was detected after 48 h. In the transplanted tumours, no effect of hormones on DNA synthesis was detected after either 24 or 48 h of culture. Synthesis of lecithin was not detectably influenced by the presence of hormones in either DMBA-induced or transplanted tumours. Oestrogen receptor concentrations were, on average, significantly higher in the DMBA-induced tumours than in either line of transplanted tumour. For 22 DMBA-induced tumours and 15 transplanted tumours, the effect of hormones in vitro (`response') was directly correlated with receptor concentration at time 0 (Spearman's ρ = + 0·59) and inversely correlated with the rate of DNA synthesis (`basal') at time 0 (Spearman's ρ = −0·62). No single parameter or pair of parameters permitted accurate distinction between the tumour types.
PRIMING EFFECT OF LUTEINIZING HORMONE RELEASING FACTOR IN VITRO: ROLE OF PROTEIN SYNTHESIS, CONTRACTILE ELEMENTS, Ca2+ AND CYCLIC AMP
Authors: PICKERING A. J.-M. C. , FINK G.
Published: December 2008

The mechanism of the priming effect of luteinizing hormone releasing factor (LH-RF) upon gonadotrophin secretion was studied using short-term incubation of hemipituitary glands from pro-oestrous rats. The dependence of the priming, but not the LH releasing action of LH-RF on protein synthesis in pituitary tissue was confirmed. Cytochalasin B failed to affect the first response to LH-RF, but abolished the priming effect, suggesting that the integrity of cellular microfilaments was essential. Colchicine and vinblastine did not modify the response to LH-RF. Neither inhibitors of DNA nor the inhibitor of RNA polymerase II, α-amanitin, significantly affected the priming action of LH-RF. Normal extracellular concentrations of Ca2+ were necessary for gonadotrophin release, but the priming effect was not significantly affected by low extracellular Ca2+ and could not be elicited by raising intracellular Ca2+ concentrations. Adenosine 3′:5′-cyclic phosphate did not appear to act as a second messenger for either the gonadotrophin releasing or the priming action of LH-RF.
GLUCOCORTICOSTEROID RECEPTORS IN THE LIVER OF NORMAL AND DECAPITATED RABBIT FOETUSES
Authors: BOURBON JACQUES , GILBERT MARC , JOST ALFRED
Published: December 2008

The affinity and the number of receptor sites for the synthetic steroid triamcinolone acetonide were studied in the livers of foetal rabbits. Twenty-two-, 24- and 29-day-old control and 29-day-old foetuses decapitated on day 22 were used to determine whether a change in steroid receptors occurs in the liver when it accumulates glycogen, and whether decapitation impairs such a change. Steroid receptors were found as early as day 22, when they were as numerous (0·091 pmol/mg protein) as on days 24 (0·098 pmol/mg) and 29 (0·104 pmol/mg). The binding affinity was found to be slightly higher on day 24 than on day 22 and it remained the same on days 24 and 29. The binding affinity of the receptors was the same in decapitated foetuses as in 29-day-old controls but the number of sites was slightly lower. The labelled steroid was transferred to the nucleus of the liver cells in vivo. It seems unlikely that steroid receptors are the limiting factor preventing the accumulation of glycogen in the liver of the rabbit foetus before day 26 or after decapitation.
INTRA-UTERINE TISSUES FROM LATE-PREGNANT RHESUS MONKEYS (MACACA MULATTA) PRODUCE 6-OXO-PROSTAGLANDIN F1α IN VITRO
Authors: MITCHELL M. D. , HICKS B. R. , THORBURN G. D. , ROBINSON J. S.
Published: December 2008

The rates of production of 6-oxo-prostaglandin F1α (6-oxo-PGF1α) in vitro by intra-uterine tissues taken from late-pregnant monkeys at Caesarean section have been determined. For tissues obtained between days 140 and 149 of pregnancy (late pregnancy) the general quantitative order of rates of production (per unit weight) was decidua basalis> placenta > decidua parietalis>amnion>chorion = myometrium. When tissues were taken between days 160 and 168 of pregnancy (near term) this order was placenta > decidua parietalis = amnion> myometrium = decidua basalis > chorion. There was a significant reduction near term in the rate of production of 6-oxo-PGF1α by decidua basalis; all other tissues exhibited similar rates of production at the two gestational periods investigated.
POSSIBLE PRIMING EFFECT OF LUTEINIZING HORMONE RELEASING HORMONE ON THE ANTERIOR PITUITARY GLAND IN THE JAPANESE QUAIL AND THE STIMULATION OF SECRETION OF FOLLICLE-STIMULATING HORMONE
Authors: DAVIES D. T. , COLLINS J.
Published: December 2008

After the i.m. injection of 10 μg synthetic LH releasing hormone (LH-RH) into Japanese quail the levels of LH and FSH in plasma rose significantly within 2 min. The increased level of LH declined rapidly but that of FSH was maintained for the duration of the experiment. To determine whether the anterior pituitary gland is primed by LH-RH a double injection schedule was adopted. It would appear that, while endogenous LH-RH may prime the avian pituitary gland slightly, synthetic LH-RH is ineffective.
ADRENOCORTICAL FUNCTION IN A FIELD POPULATION OF A MACROPODID MARSUPIAL (SETONIX BRACHYURUS, QUOY AND GAIMARD)
Authors: MILLER T. , BRADSHAW S. D.
Published: December 2008

Concentrations of corticosteroids and aldosterone have been measured in the plasma and related to the maximum cortisol binding capacity, to the concentration of sodium and potassium of the plasma and to the condition of the animals, in a natural population of the quokka (Setonix brachyurus, Quoy & Gaimard) on Rottnest Island, Western Australia. A marked population in one area has been repetitively sampled at approximately 6 week intervals over a period of 2 years. Animals were found to be in significantly better condition during the hot–dry season. Their plasma concentrations of corticosteroids, 1·09 ± 0·11 (s.e.m.) and 1·47 ± 0·14 μg/100 ml and their plasma sodium concentrations, 147 ± 0·87 and 142 ± 1·17 mequiv./l, for the hot–dry and cold–wet seasons respectively, were both significantly different (P < 0·05). Plasma concentrations of aldosterone were 8·40 ± 0·57 and 7·06 ± 0·53 ng/100 ml for the hot–dry and cold–wet seasons. The level of aldosterone fell to levels comparable to those found in salt-replete laboratory animals only during the month of July.

In the laboratory, salt deprivation resulted in a significant rise in the concentration of plasma aldosterone, 2·33 ± 0·57 (s.e.m.) ng/100 ml when salt-replete and 16·95 ± 2·74 ng/ 100 ml when salt-deprived (P< 0·001). Total plasma corticosteroid levels were unaffected by changes in the sodium content of the diet.

Injections of ACTH at a rate of 2 i.u./kg caused a significant rise in the levels of plasma corticosteroids which were essentially identical in both high- and low-condition animals. Body temperature fell to a significantly lower level in low-condition animals held in cages after injection of ACTH. These results indicate that the seasonal mortality of the quokka on Rottnest Island does not result from any breakdown in adrenal function, despite a substantial decline in the condition of the animals.
PROLONGED INTRAVENOUS INFUSION OF LABELLED IODOCOMPOUNDS IN THE RAT: [125I]IODIDE METABOLISM AND EFFECTS OF MODERATE DIETARY IODINE DEFICIENCY
Authors: BOONNAMSIRI VIPA , KERMODE J. C. , THOMPSON B. D.
Published: December 2008

Radio-iodide was administered by prolonged continuous intravenous infusion to rats maintained under iodine-replete conditions and in moderate iodine deficiency. A close approximation to equilibrium labelling was thereby achieved. Labelled iodocompounds extracted from various tissues were analysed by thin-layer chromatography.

Moderate iodine deficiency resulted in a slight increase in the ratio of mono-iodotyrosine to di-iodotyrosine in the thyroid. No change in the ratio of tri-iodothyronine (T3) to thyroxine (T4) was found in thyroid, plasma or skeletal muscle. Faecal excretion of T3 declined appreciably relative to that of T4.

Under iodine-replete conditions the ratio of thyroidal secretion rates of T3 and T4 was estimated to be more than three times higher than the ratio of these iodocompounds within the thyroid. Heterogeneity of thyroglobulin structure and function may explain these observations.
INFLUENCE OF THE PINEAL GLAND, OLFACTORY BULBS AND PHOTOPERIOD ON SURGES OF PLASMA PROLACTIN IN THE FEMALE RAT
Authors: PIEPER D. R. , GALA R. R.
Published: December 2008

The role of the pineal gland, olfactory bulbs and photoperiod in the regulation of the two daily surges of plasma prolactin in the pseudopregnant rat has been investigated. Pinealectomy had no effect on the surges of prolactin in pseudopregnant rats maintained on either a long (14 h light: 10 h darkness; 14L: 10D) or a short (2L: 22D) photoperiod, but olfactory bulbectomy decreased the nocturnal surge in animals maintained on 14L: 10D. This effect of bulbectomy was eliminated if the rats maintained on 14L: 10D were also pinealectomized. After cervical stimulation, bulbectomized rats maintained on a 2L: 22D photoperiod had nocturnal-type prolactin surges similar to those of intact rats maintained on the same photoperiod. These results indicate that the pineal gland and length of photoperiod are not involved in the regulation of the surges of plasma prolactin in pseudopregnant rats but that the olfactory bulbs may enhance the nocturnal surge.
DEPENDENCE OF TESTICULAR GERM CELLS ON HORMONES: A QUANTITATIVE STUDY IN HYPOPHYSECTOMIZED TESTOSTERONE-TREATED RATS
Authors: CHOWDHURY A. K.
Published: December 2008

Quantitative analysis of spermatogenesis was used to investigate the dependence of testicular germ cells on hormones in Sprague–Dawley rats. Adult hypophysectomized rats were given daily injections of testosterone propionate (TP) for 30 days. Intact and hypophysectomized control rats received vehicle only. Spermatogonia were classified as undifferentiated or differentiated, using established criteria suitable for morphological identification on periodic acid–Schiff's–haematoxylin stained sections of testis. Data on cell counts showed that the undifferentiated spermatogonia may be partially dependent on TP and/or pituitary hormones. The group of differentiated spermatogonia were dependent on pituitary hormones, and TP only partially restored their number by partially protecting them from spontaneous degeneration in stages XIV to II (A3-to-Intermediate). The maturation and division of B type spermatogonia and maturation of preleptotene spermatocytes to the zygotene stage appeared to be independent of hormones. Maturation of pachytene spermatocytes was hormone dependent, and TP completely supported their development, meiotic division and spermiogenesis in the complete absence of pituitary hormones.
OVARIAN ACTIVITY, AND TOTAL GONADOTROPHIN AND GONADOTROPHIN RELEASING HORMONE LEVELS IN RESPONSE TO SOME SYNTHETIC NON-STEROIDAL OVULATING AGENTS IN THE CATFISH, HETEROPNEUSTES FOSSILIS (BLOCH)
Authors: SINGH T. P. , SINGH A. K.
Published: December 2008

Effects of clomiphene citrate, cyclofenil and prostaglandins (PGE1 and PGF2α) on ovarian 32P uptake, on gonadotrophin levels in the pituitary gland and blood serum and on a gonadotrophin releasing hormone-like (GnRH-like) substance in the hypothalamus were investigated in Heteropneustes fossilis. These drugs were very effective in increasing the serum level of gonadotrophin with a subsequent increase in ovarian 32P uptake in sham-hypophysectomized recipients. All the drugs except cyclofenil failed to stimulate 32P incorporation by the ovary in hypophysectomized fish. Clomiphene citrate and cyclofenil also induced a significant increase in the GnRH-like factor in the hypothalamus of H. fossilis. Such a response was not obtained in fish treated with PGE1 and PGF2α. It seems likely that the action of clomiphene is routed through the hypothalamo-pituitary-ovarian axis and that of prostaglandins directly through the pituitary-ovarian axis. The action of cyclofenil is bimodal; one effect like that of clomiphene and the other direct upon the ovary probably by increasing its sensitivity to the available gonadotrophin.
CYCLICAL CHANGES IN CONCENTRATIONS OF α-MELANOTROPHIN IN THE PLASMA OF MALE AND FEMALE RATS
Authors: WILSON J. F. , MORGAN MERRILL A.
Published: December 2008

Radioimmunoassay measurements of α-melanotrophin in plasma have identified a diurnal rhythm in male rats. Animals maintained on a 12 h light: 12 h darkness photoperiod had raised levels of plasma α-melanotrophin during the dark phase. Time-series analysis gave a fitted mean level of α-melanotrophin of 52·4 pmol/l, an amplitude of 12·1 pmol/l and peak levels 2·2 h before dawn.

Measurements throughout the oestrous cycle in female rats showed that similar variations between the dark and light phases occurred on the 2 days of dioestrus. The raised levels during the dark period were, however, absent on the nights of pro-oestrus and oestrus. During this pro-oestrous/oestrous period, plasma α-melanotrophin levels were below average but higher than the normal minimum levels found during the light period.
REDUCTION OF ANDROSTENEDIONE BY SKIN IN VITRO AND SERUM LEVELS OF GONADOTROPHINS AND ANDROGENS IN MEN WITH HYPOSPADIAS
Authors: SVENSSON JAN , ENEROTH PETER , GUSTAFSSON JAN-ÅKE , RITZÉN MARTIN , STENBERG ÅKE
Published: December 2008

The reduction of 4-[1,2-3H]androstene-3,17-dione (androstenedione) in vitro by scrotal skin was measured in samples from nine men (16–34 years old) with hypospadias and from ten male control subjects. The reduction of androstenedione was also studied in axillary and upper arm skin of seven control subjects. Androstenedione was reduced to material with chromatographic characteristics of 5α-androstane-3,17-dione and to 3α- and 3β-hydroxy-5α-androstan-17-one.

No difference in 5α-reductase activity (defined as the sum of these three metabolites formed) was found in scrotal skin from hypospadic and control men.

The mean concentration of 5α-dihydrotestosterone in serum from men with hypospadias was lower than that in serum from control subjects (P< 0·01). The mean ratio of the serum concentrations of testosterone and 5α-dihydrotestosterone was higher in hypospadic men than in control subjects (P< 0·05). No differences between the two groups were found in the mean serum concentrations of LH, FSH, prolactin, dehydroepiandrosterone, androstenedione, testosterone or testosterone-binding globulin.
EFFECTS OF LESIONS OF THE SUPRACHIASMATIC NUCLEI AND OF p-CHLOROPHENYLALANINE ON THE CIRCADIAN RHYTHMS OF ADRENOCORTICOTROPHIC HORMONE AND CORTICOSTERONE IN THE PLASMA, AND ON LOCOMOTOR ACTIVITY OF RATS
Authors: SZAFARCZYK A. , IXART G. , MALAVAL F. , NOUGUIER-SOULÉ J. , ASSENMACHER I.
Published: December 2008

Adrenocorticotrophin (ACTH) and corticosterone in the plasma of adult female rats were measured sequentially at 4 h intervals for 24 h before and after lesions of the suprachiasmatic nuclei or treatment with p-chlorophenylalanine (to inhibit serotonin synthesis). After lesions or p-chlorophenylalanine treatment, the concentrations of ACTH were diminished relative to those in control animals and rhythmic changes could not be detected. However, injection of animals, pretreated with p-chlorophenylalanine, with 5-hydroxytryptophan (60 mg/kg) 8 h before the time when plasma ACTH is maximal in intact animals, stimulated ACTH secretion up to control values. Mean corticosterone concentrations in plasma remained unchanged (after lesions) or increased (after p-chlorophenylalanine). This increase was associated with an increased minimal concentration of corticosterone. After both treatments there was evidence of continued circadian or ultradian rhythms of corticosterone concentration.

Locomotor activity of female rats given identical treatment, but without blood sampling, indicated that nocturnal activity was diminished after lesions whereas diurnal activity was enhanced after p-chlorophenylalanine treatment. Periodicity analysis detected the persistence of free-running circadian, and sometimes ultradian activity, rhythms. Adrenalectomy did not alter further the activity pattern observed in rats with lesions.

These results therefore support the proposition that both the suprachiasmatic nuclei and the serotoninergic system play an irreplaceable role in the mechanism of ACTH secretory rhythms. The suprachiasmatic nuclei are also important for synchronization of locomotor activity and corticosterone rhythms, which may both persist after the suppression of ACTH rhythms.
ANNUAL RHYTHMS OF LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, PROLACTIN AND TESTOSTERONE IN THE SERUM OF MALE RHESUS MONKEYS
Authors: BECK W. , WUTTKE W.
Published: December 2008

Six male rhesus monkeys were kept under rigidly controlled conditions for 1–2 years. During August of the first year a thyrotrophin releasing hormone (TRH) test was performed on each of the monkeys by giving 10 μg TRH as a bolus injection. Significantly increased serum prolactin levels occurred 15 min after the injection. After a training period of 2 months, during which blood samples were collected every other day by puncture of the saphenous vein, blood was collected three times a week for 14 months. Serum levels of prolactin, LH, FSH and testosterone were measured by radioimmunoassay. Mean serum prolactin levels increased significantly during June, July and August in all six animals. Peak levels were observed in August and September and then levels declined gradually to reach a minimum in April and May. Mean serum testosterone levels closely paralleled the annual pattern of prolactin. Mean serum LH levels significantly decreased during the time when mean serum prolactin and testosterone levels were increasing and they increased again at the time of decreasing mean prolactin levels, i.e. mean serum LH and prolactin were negatively correlated. In individual monkeys, however, a rigid negative correlation between serum prolactin and LH could not be demonstrated. Mean serum FSH levels did not change significantly.
IMMUNOLOGICAL RELATIONSHIPS AMONG OVINE GLYCOPROTEIN HORMONES
Authors: SAIRAM M. R.
Published: December 2008

An antiserum to partially purified ovine FSH (but essentially free of LH) bound 125I-labelled ovine LH or bovine TSH. The antibody was directed exclusively against determinants in the α subunit. In a radioimmunoassay, only the intact ovine and bovine hormones and their α subunits were reactive; the hormone specific β subunits exhibited no cross-reaction. The antibody directed against the α subunit was highly dependent on conformation. Human LH, FSH, TSH or their α subunits did not cross-react in the radioimmunoassay. Structural modifications such as acylation of the amino groups, reduction and alkylation of the S—S-bridges, or performic acid oxidation of the intact ovine FSH, LH or their α subunits virtually eliminated immunological reactivity. Using the α subunit radioimmunoassay, the presence of a significant quantity of free intact α subunit in standard (NIH) preparations of TSH-B7, FSH-S10 and LH-S19 was demonstrated.
ACTION OF OESTROGENS AND ANTIOESTROGENS ON OESTROGEN-INDUCIBLE CYTOPLASMIC AND ANDROGEN-INDUCIBLE MICROSOMAL ACTIVITY OF 3α-HYDROXYSTEROID DEHYDROGENASE IN MALE RAT KIDNEY
Authors: GHRAF R. , LAX E. R. , SCHRIEFERS H.
Published: December 2008

The influence of steroidal and non-steroidal antioestrogenic compounds on the effect of systemically administered oestradiol (OE2) and diethylstilboestrol (DES) was investigated in adult male rats with intact gonads. In this animal model, oestrogens induced the NADP-dependent cytoplasmic activity and prevented the inductive action of androgens on NADP-dependent microsomal activity of renal 3α-hydroxysteroid dehydrogenase (3α-HSDH). Simultaneous administration of tamoxifen (0·5 mg/day) with OE2 (5 μg/day) or DES (10 μg/day) for 10 days completely blocked the inductive effect of OE2 on cytoplasmic 3α-HSDH, whereas, in the case of the microsomal enzyme, the repressive effects of OE2 and DES were antagonized only to 28 and 16% respectively. Simultaneous administration of 5α-dihydrotestosterone (DHT; 0·5 mg/day) for 10 days antagonized the inductive effect of OE2 on the cytoplasmic enzyme activity to 86% and completely by-passed the repressive effects of OE2 and DES on the microsomal enzyme activity.

It is concluded that oestrogenic induction of renal cytoplasmic 3α-HSDH involves an oestrogen receptor mechanism which, in this animal model, can be antagonized by tamoxifen. In contrast, oestrogenic repression of renal microsomal 3α-HSDH is obviously the consequence of the strong antigonadotrophic activity of oestrogens leading to subsequent repression of testicular androgen secretion by mechanisms which can be only weakly antagonized by tamoxifen. Exogenous DHT, even in the presence of OE2 or DES, completely compensates for this centrally mediated deficit of peripheral androgen.
EXAMINATION OF THE ROLE OF 'NON-FUNCTIONAL' CORPORA LUTEA IN THE FEMALE RAT
Authors: DE GREEF W. J. , VAN DER SCHOOT P.
Published: December 2008

In rats with 5 day reproductive cycles, 'anovulatory' cycles were induced by blockade of ovulation with sodium pentobarbitone injected at pro-oestrus. Such anovulatory cycles were characterized in the ovaries by gradual atresia of the large follicles present at the time of the injection and the growth of a new cohort destined for the next ovulation. In the vaginal smears, anovulatory cycles were indistinguishable from normal ovulatory cycles.

The serum concentrations of progesterone remained at baseline levels during dioestrus of anovulatory cycles whereas increased concentrations of progesterone were observed during dioestrus of ovulatory cycles. It is concluded that the 'non-functional' corpora lutea of the cycle are the source of dioestrous progesterone.

The length of anovulatory cycles after a single injection of pentobarbitone was 5 days despite the absence of any increase in progesterone concentrations during dioestrus. It is concluded that progesterone production during dioestrus plays no major role in the control of the duration of 5 day reproductive cycles.
METABOLISM OF TESTOSTERONE BY THE EPITHELIUM AND MESENCHYME OF THE RAT UROGENITAL SINUS
Authors: BARD D. R. , LASNITZKI ILSE , MIZUNO T.
Published: December 2008

Testosterone metabolism was measured in separated epithelium and mesenchyme from the urogenital sinuses of 17- and 19-day-old male and female rat embryos and compared with testosterone metabolism in the intact sinus. Both the epithelium and the mesenchyme converted testosterone to 5α-dihydrotestosterone. The epithelium produced much more androstanedione and androsterone but less 3α,17β-androstanediol than did the mesenchyme. The whole sinus synthesized all four metabolites, but in different proportions, producing relatively more androsterone than either of its two component tissues. These data suggest that androsterone is formed by the joint action of epithelium and mesenchyme. Metabolism of testosterone did not differ with sex or foetal age in either of the separated tissues or in the intact sinus, implying that the failure of urogenital mesenchyme from 19-day-old female foetuses to induce prostatic morphogenesis is not due to the loss of 5α-reductase. It is suggested that this lack of inductive capacity may be attributable to a decline in androgen levels with age in female mesenchyme.
CHRONIC ALDOSTERONE THERAPY AND THE CONTROL OF TRANSEPITHELIAL TRANSPORT OF IONS AND WATER BY THE COLON AND COPRODEUM OF THE DOMESTIC FOWL (GALLUS DOMESTICUS) IN VIVO
Authors: THOMAS D. H. , SKADHAUGE ERIK
Published: December 2008

White Leghorn laying hens were maintained on commercial poultry food (medium-Na+ diet) and fresh water. Birds maintained on a high-Na+ diet received, in addition, 10 ml 9% (w/v) NaCl/kg by stomach load for 2 days before the perfusion experiments. Some birds on each dietary Na+ level also received aldosterone injections (60 μg/kg per day, i.m.) for 2 days before the perfusion experiments. The lumen of the coprodeum and colon of anaesthetized birds was perfused with solutions resembling ureteral urine, with systematically varied Na+, NH4+, Cl− and osmotic concentrations. Aldosterone enhanced net Na+ absorption (JNa) and associated net Cl− absorption and K+ secretion, and induced (in birds on medium-but not on high-Na+ diets) the appearance of a saturable JNa component dependent on the luminal concentration of Na+. Aldosterone enhanced net absorption of NH4+ and decreased the transmural potential difference in birds on a high-Na+ diet only; water and phosphate fluxes were not affected. Disparities between aldosterone- and Na+-depletion-induced effects suggested that one or more factors (in addition to aldosterone) are involved in the normal mediation of the responses of the lower intestine of the domestic fowl to varied Na+ intake.
A SEXUALLY DIMORPHIC RHYTHM IN OESTRADIOL-ACTIVATED LORDOSIS BEHAVIOUR IN THE RAT
Authors: HANSEN S. , SÖDERSTEN P. , ENEROTH P. , SREBRO B. , HOLE K.
Published: December 2008

Ovariectomized rats exposed to constant plasma levels of oestradiol showed a daily rhythm in lordosis behaviour, with high levels of lordosis occurring during the dark portion of the daily light: darkness cycle and low levels during the light period. Similarly treated male rats failed to show a rhythm in lordosis behaviour. However, neonatal castration permitted the expression of the lordosis rhythm in male rats; conversely, an injection of 1·25 mg testosterone propionate on day 4 of life abolished the rhythm in female rats. Pinealectomy, adrenalectomy or depletion of brain 5-hydroxytryptamine levels did not affect the periodicity in lordosis behaviour but lesions in the suprachiasmatic nuclei of the hypothalamus disrupted the rhythm. It is suggested that the daily rhythm in lordosis behaviour participates in the control of the termination of heat in the female rat and that the perinatal hormone milieu may exert permanent effects on periodic functions.
OESTROGEN RECEPTORS IN CELL NUCLEI OF THE HYPOTHALAMUS-PREOPTIC AREA-AMYGDALA FOLLOWING AN INJECTION OF OESTRADIOL OR THE ANTIOESTROGEN CI-628
Authors: ROY E. J. , McEWEN B. S.
Published: December 2008

Oestrogen receptors were measured by an exchange assay in cell nuclei of the hypothalamus–preoptic area-amygdala (HPA) of ovariectomized-adrenalectomized (OVX-ADX) rats following an intravenous injection of oestradiol or an antioestrogen, CI-628. Receptors were translocated to the nucleus by both compounds. Receptors translocated by the antioestrogen were specific for oestrogens; testosterone, corticosterone and progesterone were not bound by these receptors. Several properties of antioestrogen– and oestradiol–receptor complexes were compared.

The time-course in cell nuclei in vivo showed that receptors were still present in HPA nuclei 24 h after administration of CI-628 but not 24 h after oestradiol. This prolonged increase of nuclear receptors after the antioestrogen treatment was attributed to the continued presence of CI-628 and its metabolites in plasma.

The maximum level of receptors produced in the HPA cell nuclei following CI-628 treatment was lower than the peak level of nuclear receptors following oestradiol. The dissociation rate in vitro of nuclear antioestrogen–receptor complexes formed in vivo was more rapid at 0 °C than that of nuclear oestradiol–receptor complexes. This property may be related to the lower peak level of binding after CI-628 treatment and to the inhibitory actions of antioestrogens.