bluuebunny/crossref_metadata_2025 huggingface dataset:
PROPERTIES OF RAT ADRENAL ZONA RETICULARIS CELLS: PREPARATION BY GRAVITATIONAL SEDIMENTATION
Authors: BELL J. B. G. , GOULD R. P. , HYATT P. J. , TAIT J. F. , TAIT S. A. S.
Published: December 2008

An enriched fraction of zona reticularis cells was obtained by unit gravity sedimentation of decapsulated adrenal glands from female rats. From light microscopic and ultrastructural studies of the whole gland and the isolated cell fractions, the zona reticularis cells of the adrenal gland can be classified mainly on the bases of size, position and mitochondrial morphology. This cell population consists of two types of cell, the 'true' zona reticularis cells (Type I, modal diameter 9 μm), which usually constitute 90% of the isolated reticularis fraction and 80% of the intact reticularis tissue, and cells (Type II, modal diameter 13 μm) with fasciculata-like properties (rich in lipid and spherical mitochondria with vesicular cristae). Staining of the cell preparation for 3β-hydroxysteroid dehydrogenase activity also demonstrates the existence of two types of cell in the zona reticularis.

The zona reticularis cell fraction, like the zona fasciculata cell fraction, was capable of producing the subsequent steroids from radioactive pregnenolone: corticosterone, deoxycorticosterone, 18-hydroxydeoxycorticosterone, 11-dehydrocorticosterone, progesterone and androstenedione. However, the pattern of steroid production differed markedly between the zona reticularis and zona fasciculata cells, particularly with respect to the production of deoxycorticosterone and corticosterone (and its correlated steroids, 11-dehydrocorticosterone and 18-hydroxydeoxycorticosterone). When R (the ratio of deoxycorticosterone: corticosterone plus 11-dehydrocorticosterone) for the purest preparation of reticularis cells was compared with R for the corresponding preparation of fasciculata cells, the normalized ratio was found to be 6·4, 16·4 and 20·1 in three experiments. The pattern of production of androstenedione per cell was similar in the reticularis and fasciculata cell fractions. The exact mechanism for the altered pattern of steroid metabolism remains to be elucidated. However, these results establish that the corticosteroids produced by the cells of the zona reticularis may be quantitatively, if not qualitatively, different from those produced by the zona fasciculata cells.
ANDROGEN BINDING IN CYTOSOLS AND NUCLEI OF HUMAN BENIGN HYPERPLASTIC PROSTATIC TISSUE
Authors: SIRETT D. A. N. , GRANT J. K.
Published: December 2008

Androgen binding sites have been detected in cytosols and nuclear extracts from human benign hyperplastic prostatic (BPH) tissue with exchange assays using [3H]methyltrienolone and [3H]5α-dihydrotestosterone respectively. The concentrations of binding sites and the equilibrium dissociation constants for the [3H]steroid–receptor interactions have been determined and the specificity of the binding has been examined. The observed properties of the binding sites are consistent with those characteristic of androgen receptors.

The binding sites are present in nuclear extracts from all BPH tissue samples examined to date. The amount of binding detected in the nuclear fraction is higher than that found in the cytosol.
INSULIN AND GLUCOSE LEVELS IN ACUTE AND CHRONICALLY URAEMIC RATS
Authors: SAEED AMAL M. , EL MUNSHID H. A. , SUKKAR M. Y. , ABDEL WAHAB S. M.
Published: December 2008

Departments of Physiology and Pathology, Faculty of Medicine, University of Khartoum, P.O. Box 102, Khartoum, Sudan

(Received 31 October 1977)

The important role of the kidney in the degradation and excretion of insulin has recently been reviewed (Rubenstein & Spitz, 1968; Rubenstein, Mako & Horwitz, 1975). The kidney functions with a wide margin of safety but the minimum functional renal mass required for the effective elimination of insulin is not known. The present report deals with the effects of total and five-sixths nephrectomy on the concentrations of insulin and glucose in the blood. The effects of uraemia itself, produced by bilateral ureteric ligation, have also been studied.

Albino rats of the Wistar strain (mean weight 232 ± 5 (s.e.m.) g) were used. Except for ten female rats included in the acutely uraemic group, the remainder of the animals were male. The subsequent operations were performed under open diethyl ether anaesthesia
POSTMATURITY IN THE RAT: HIGH LEVELS OF GLUCAGON IN THE PLASMA OF THE FOETUS AND NEONATE
Authors: PORTHA B. , PICON L. , ROSSELIN G.
Published: December 2008

*Laboratoire de Physiologie du Développement, Tour 23/33, Université Paris VII, 2 Place Jussieu, 75005 Paris, France and †Unité de Recherches de Diabétologie et d'Etudes Radio-Immunologlques des Hormones Protéiques, U.55 (INSERM), Hôpital Saint-Antoine, 184 Rue du Faubourg Saint-Antoine, 75012 Paris, France

(Received 1 November 1977)

Experimental prolonged gestation in the rat results in a reduction in the amounts of insulin and glucagon accumulated in the pancreas, a low level of insulin in the plasma and a sharp depletion of hepatic glycogen stores (Portha, Rosselin & Picon, 1976). Moreover, in the liver of the postmature foetus the activities of the main glyconeogenic enzymes, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, are increased (Portha, Le Provost, Picon & Rosselin, 1978). The present study was undertaken to investigate the effects of glucagon in the circulation on these processes.

Gestation was prolonged by s.c. administration of progesterone to the mother (2·5 mg/rat) once daily on days 20·5, 21·5
DEVELOPMENT AND CHARACTERIZATION OF A HOMOLOGOUS RADIOIMMUNOASSAY FOR BOVINE FOLLICLE-STIMULATING HORMONE
Authors: CHENG KWONG-WAH
Published: December 2008

A radioimmunoassay for bovine FSH has been developed using a rabbit antiserum against highly purified bovine FSH (160 × NIH-FSH-S1) and a 125I-labelled tracer of the same preparation. The sensitivity was 0·25 ng/ml for purified bovine FSH or 25 ng/ml with reference to a crude bovine FSH (NIH-FSH-B1) standard. Purified bovine LH and TSH showed cross-reactivities of less than 1%, while their subunits and other purified protein hormones showed no significant inhibition at concentrations up to 100 ng/ml. Ovine FSH cross-reacted significantly but in a non-parallel manner; human and rat FSH cross-reacted only slightly. The concentrations of FSH (means ± s.e.m.) in the sera of cows (n = 12), cows at oestrus (4), bulls (7) and steers (9) were measured as 25·4 ± 4·7, 58·4 ± 12·6, 45·7 ± 9·5 and 120·2 ± 36·0 ng/ml respectively. The FSH content of bovine pituitary glands varied greatly between individuals, from 2 to 25 μg/mg tissue. The inhibition curves of pituitary and serum FSH were parallel to that of the bovine FSH standard.
EFFECT OF LOW CALCIUM AND LOW PHOSPHORUS DIETS ON THE INTESTINAL ABSORPTION OF PHOSPHATE IN INTACT AND PARATHYROIDECTOMIZED PIGS
Authors: FOX J. , CARE A. D.
Published: December 2008

The intestinal absorption of phosphate has been studied in conscious pigs, each prepared with a Thirty–Vella loop of jejunum. The feeding of diets low in either calcium or phosphorus caused a significant increase in the efficiency of absorption of phosphate from the solution used to perfuse the jejunal loop in both intact and parathyroidectomized (PTX) pigs. An intravenous infusion of parathyroid hormone (0·22 u. kg−1 h−1) into a PTX pig also enhanced the absorption of phosphate. The increase in the absorption of phosphate when the low phosphorus diet was fed was not caused by an increase in the concentration gradient of phosphate ions between the jejunal lumen and blood.

It is concluded that the intestinal absorption of phosphate shows similar changes to those of calcium when diets low in calcium or phosphorus are fed and that parathyroid hormone, although capable of stimulating the absorption of phosphate, is not essential for this adaptation. These effects are probably brought about by changes in the renal production and mucosal uptake of 1,25-dihydroxycholecalciferol, the active metabolite of vitamin D3.
SULPHATION FACTOR (SOMATOMEDIN ACTIVITY) IN EXPERIMENTAL PROTEIN MALNUTRITION IN THE RAT
Authors: SHAPIRO B. , PIMSTONE B. L.
Published: December 2008

In a rat model of protein malnutrition in which the failure of growth is a major feature, a low level of bioassayable sulphation factor activity was present in the serum, associated with normal levels of growth hormone and low insulin in the plasma. The administration of pharmacological doses of human or bovine growth hormone did not increase the amount of sulphation factor activity in the serum or the width of the tibial epiphyses in the proteinmalnourished animals. The basal and serum-stimulated incorporation of 35SO42− into the costal cartilages of malnourished animals did not differ from that of controls, which suggests that the responsiveness of the end-organs was normal.
MACROSCOPIC IDENTIFICATION AND STEROIDOGENIC FUNCTION OF ATRETIC FOLLICLES IN SHEEP
Authors: MOOR R. M. , HAY MARY F. , DOTT H. M. , CRAN D. G.
Published: December 2008

The degree of translucency, vascularization of the follicle wall and the integrity of the membrana granulosa, as seen under a stereoscopic microscope, were used to distinguish between non-atretic and atretic isolated follicles. Subsequent histological evaluation showed that both non-atretic and severely atretic follicles could be correctly identified with over 95% accuracy.

The concentrations of steroids were measured in both follicular tissue and fluid. The total steroid content of large (3·1–6·0 mm diameter) non-atretic follicles in vivo (115 pmol/follicle) exceeded that of large atretic follicles (54 pmol) and also that of small (2·0–3·0 mm diameter) non-atretic and atretic follicles (6 pmol). Oestrogen accounted for 80%, testosterone 13% and progesterone 7% of the total steroid content in large non-atretic follicles, whereas testosterone accounted for 75% of the steroid content in the other three categories of follicles. A similar pattern is observed when the concentrations of steroids are expressed on the basis of follicular weight.

Total oestrogen secretion, as measured by the output of steroid into the culture medium in 24 h, was 937 pmol for large non-atretic, 31 pmol for large atretic, 65 pmol for small nonatretic and 4 pmol for small atretic follicles. In terms of steroid production (pmol/mg tissue), the four follicular categories were equally efficient. However, the type of steroid produced depended on the category of follicle and corresponded to its steroid content.
EFFECTS OF OESTROGEN AND/OR PITUITARY GRAFTS ON NUCLEIC ACID SYNTHESIS IN THE MAMMARY GLANDS OF LACTATING MICE
Authors: NAGASAWA HIROSHI , YANAI REIKO
Published: December 2008

The mammary gland synthesizes little DNA during lactation in mice. The effects of daily injections of oestradiol benzoate (OB) between days 9 and 11 of lactation, and/or grafting with three isologous anterior pituitary glands on day 1, on the growth of the litter and the development and function of mammary glands were studied on day 12 of lactation in C3H/He mice.

The level of prolactin in the plasma of mice with pituitary grafts was raised, but mammary gland function was not affected. The synthesis and content of mammary gland RNA was depressed after injection of 0·5 μg OB/day; at a dose of 10 μg/day, OB also depressed litter growth and mammary DNA content, but increased the synthesis of DNA and the level of prolactin in the plasma. Pituitary grafting enhanced the effect of 10 μg OB/day on DNA synthesis. These findings suggest that one of the causes of the low level of DNA synthesis in the mammary gland during lactation in mice is a low level of oestrogen in the circulation.
EFFECT OF OVINE LUTEINIZING HORMONE ON THE SECRETION OF PROGESTERONE IN VITRO BY OVARIAN FOLLICLES FROM HYPOPHYSECTOMIZED RATS TREATED WITH FOLLICLE-STIMULATING HORMONE
Authors: LABARBERA A. R. , NOCENTI MERO R.
Published: December 2008

Department of Physiology, College of Physicians and Surgeons, Columbia University, New York 10032, U.S.A.

(Received 14 November 1977)

Ovarian follicles from oestrous, pro-oestrous and hypophysectomized rats have the capacity to secrete progestins in vitro and to respond to luteinizing hormone (LH) by increasing this secretion (Stoklosowa & Nalbandov, 1972; LaBarbera, Nocenti & Castellano, 1974; Lindner, Tsafriri, Lieberman, Zor, Koch, Bauminger & Barnea, 1974). Follicles from hypophysectomized rats, untreated or treated with follicle-stimulating hormone (FSH), were therefore studied in experiments in vitro to investigate further the gonadotrophic control of progesterone secretion.

Mature virgin female rats (200–250 g) were hypophysectomized and, beginning on day 4 after the operation, received a total of 360 μg ovine FSH (NIH-FSH-S9)/100 g body weight, injected s.c. in corn oil as six divided doses, one every 12 h for 3 days. Untreated controls received corn oil only. On day 7 after hypophysectomy, the ovaries were excised and
EFFECT OF CHRONIC REMOVAL OF TESTICULAR FLUID ON THE RELEASE OF FOLLICLE-STIMULATING HORMONE IN HEMICASTRATED RAMS
Authors: WALTON J. S. , EVINS JANET D. , WAITES G. M. H.
Published: December 2008

Department of Physiology & Biochemistry, The University, Whiteknights, Reading, RG6 2AJ

(Received 29 November 1977)

Testicular fluid (RTF) collected from rams in this laboratory has been shown to contain 'inhibin', which selectively inhibits the release of follicle-stimulating hormone (FSH) in rats (Franchimont, Chari, Hazee-Hagelstein, Debruche & Duraiswami, 1977). During these collections, the possibility that diversion of RTF from the remaining testis of hemicastrated rams might provide further evidence about the feedback control of FSH was examined.

Eight mature Clun Forest rams, hemicastrated at least 3 months previously, were placed in metabolism crates in a room with natural lighting for 7 days, after which the extratesticular rete of the remaining testis was cannulated (Voglmayr, Scott, Setchell & Waites, 1967) under general anaesthesia. Each ram was returned to its crate, where it was supported by a canvas harness during the collection of RTF (Edwards, Dacheux & Waites, 1976). The operations were performed
A 24 HOUR RADIOIMMUNOASSAY FOR HUMAN PROLACTIN
Authors: GWEE H. M. , MASHITER K.
Published: December 2008

The Endocrine Unit, Department of Medicine, Royal Postgraduate Medical School, Du Cane Road, London, W12 OHS

(Received 16 December 1977)

Radioimmunoassays for prolactin described previously require incubation periods of 3–8 days (Hwang, Guyda & Friesen, 1971; Sinha, Selby, Lewis & Vanderlaan, 1973; Aubert, Becker, Saxena & Raiti, 1974). In our studies on prolactin secretion by human pituitary adenomas (Mashiter, Adams, Beard & Holley, 1977; Trinder, Barratt, Sood, Holley, van Noorden, Joplin & Mashiter, 1977), we were anxious to obtain assay data more rapidly in order to maximize the experimental life of each preparation. This report describes a 24 h assay which retains the characteristics of our existing 7 day assay with which it is compared.

Human prolactin VLS 1 was used as standard, human prolactin VLS 3 for iodination and rabbit anti-VLS 3 as antiserum, all generously donated by the National Pituitary Agency, NIAMDD, U.S.A. Labelled Na125I (IMS 30) was
OBSERVATIONS ON THE LOCALIZATION OF LABELLED AMINO ACID IN MOUSE ADRENAL CHROMAFFIN CELLS AFTER THE INJECTION OF l-[4,5-3H]LEUCINE
Authors: KOBAYASHI S. , KENT CHRISTINE , COUPLAND R. E.
Published: December 2008

The intracellular localization of l-[4,5-3H]leucine in chromaffin cells has been observed using light and electron microscopic autoradiography and the association of the labelled amino acid with particular cell components confirmed by statistical analysis. By making observations at short intervals after a single intravenous pulse of [3H]leucine it has been possible to follow the movement of the isotope from the endoplasmic reticulum through the Golgi complex to the chromaffin granules. No evidence for movement of the label through the Golgi complex was observed in adjacent cortical cells. The time sequence of transport of the amino acid through the various cell organelles was very similar to that observed by previous workers in protein-secreting exocrine cells.
SOLUBILIZATION AND PARTIAL CHARACTERIZATION OF HUMAN AND PORCINE THYROTROPHIN RECEPTORS
Authors: DAWES P. J. D. , PETERSEN V. B. , REES SMITH B. , HALL R.
Published: December 2008

Thyrotrophin (TSH) receptors have been extracted from human and porcine thyroid membranes by treatment with Triton X-100.125I-Labelled bovine TSH was used to monitor receptor activity. Analysis by gel filtration and electrophoresis on acrylamide gels containing sodium dodecyl sulphate suggested that Triton extracts of human thyroid membranes contained TSH receptors with a molecular weight in the region of 50 000 closely associated with Triton micelles of approximate molecular weight 300 000. Isoelectric focusing studies indicated that the Triton-solubilized TSH binding activity had an isoelectric point of pH 4–4·5. The soluble TSH receptors were heat-labile, showed optimum TSH binding at pH 7·4 and reduced hormone binding at high ionic strength. The TSH binding characteristics of membrane-bound and solubilized human TSH receptors were similar and both preparations gave curved Scatchard plots.

Solubilized porcine TSH receptors appeared to have a similar molecular weight to the human receptors and were also closely associated with Triton micelles of approximate molecular weight 300 000. Scatchard analysis of TSH binding to membrane-bound or solubilized porcine TSH receptors gave approximately linear plots with association constants of 2·8 ± 0·95 (s.e.m.) × 109 and 1·7 ± 0·27 × 1091/mol respectively. Comparison of the binding capacities of the solubilized and membrane-bound porcine receptors indicated that the 0·5% Triton extracts contained 40% of the original TSH binding activity and that this was present at a concentration of 25 ng/ml.
POSTOVULATORY LEVELS OF PROGESTOGENS, OESTROGENS, LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN THE PLASMA OF AGED GOLDEN HAMSTERS EXHIBITING A DELAY IN FERTILIZATION
Authors: PARKENING T. A. , SAKSENA S. K. , LAU I. F.
Published: December 2008

* Department of Anatomy, University of Texas Medical Branch, Galveston, Texas 77550, U.S.A. and †The Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545, U.S.A.

(Received 5 December 1977)

Fertilization is delayed approximately 2–5 h in the majority of ova recovered from aged hamsters (14–17 months old), compared with younger (3–5 months old) animals (Parkening & Soderwall, 1975). This delay may explain the relatively large percentage (40%) of ova which is incapable of developing to the implantation stage in this species (Parkening & Soderwall, 1975). Blaha & Leavitt (1974) have shown that there is a wider variation in the peripheral plasma concentration of progesterone at the time of fertilization in aged than in younger hamsters. A hormonal imbalance in the senescent female hamster may disturb normal gamete interactions, thus causing the delay in fertilization. In order to determine the significance of hormonal levels with respect to fertilization, the concentrations of progestogens,
EFFECTS OF OVARIECTOMY AND TREATMENT WITH PROGESTERONE OR OESTRADIOL-17β ON THE SECRETION OF INSULIN BY THE PERFUSED RAT PANCREAS
Authors: LENZEN S.
Published: December 2008

Institut für Pharmakologie und Toxikologie, Universität Göttingen, Robert-Koch-Strasse 40, D-3400 Göttingen, Germany

(Received 17 January 1978)

Hyperinsulinaemia caused by female sex hormones has been attributed to increased insulin secretion by the pancreatic β-cells (Costrini & Kalkhoff, 1971; Hager, Georg, Leitner & Beck, 1972), but investigation of this hypothesis has been hampered by methodological difficulties. Treatment of the rat with female sex hormones may affect quantitative and qualitative yields of pancreatic islets after collagenase digestion of the pancreas and may increase the glucose-induced insulin release from the islets when the number of islets, but not the protein content, is chosen as the reference parameter (Costrini & Kalkhoff, 1971). Similarly, treatment with female sex hormones may affect the contamination of pancreatic islets with non-islet cells and therefore alter the islet protein content. Since protein content is used as a reference parameter, values for the rate of release of insulin from the pancreatic
PRODUCTION OF THROMBOXANE B2 BY INTRA-UTERINE TISSUES FROM PREGNANT GOATS IN VITRO
Authors: MITCHELL M. D. , FLINT A. P. F. , KINGSTON E. J. , THORBURN G. D. , ROBINSON J. S.
Published: December 2008

Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU

(Received 9 February 1978)

It has been shown that prostaglandins play an important role in the mechanism of parturition in many species, including the goat (Currie & Thorburn, 1977; Thorburn, Challis & Robinson, 1977). Recently we have demonstrated that intra-uterine tissues from pregnant goats, when superfused in vitro, produce prostaglandins E and F (PGE, PGF) and 13,14-dihydro-15-oxo-prostaglandin F at various rates (Mitchell, Flint, Robinson & Thorburn, 1978). The exciting discoveries of two potent prostaglandin-like compounds, thromboxane A2 (TXA2; Hamberg, Svensson & Samuelsson, 1975) and prostacyclin (PGI2; Moncada, Gryglewski, Bunting & Vane, 1976), have radically altered our thinking on prostaglandins and basic data are urgently required concerning these compounds. Since prostaglandin endoperoxides are the immediate precursors of both prostaglandins and TXA2 (and PGI2) and since TXA2 has been shown to cause contraction of a number
ELIMINATION OF INFUSED ARGININE-VASOPRESSIN AND ITS LONG-ACTING DEAMINATED ANALOGUE IN RATS
Authors: GAZIS DIANA , SAWYER W. H.
Published: December 2008

Arginine-vasopressin (AVP) and deamino-arginine-vasopressin (dAVP) were infused into rats. When the concentrations of the two peptides were steady, the rate of clearance of AVP from the plasma was six times the rate of clearance of dAVP. Only 6% of the infused AVP was excreted unchanged in the urine, whereas approximately 100% of the dAVP was excreted. When the infusions were stopped, AVP disappeared from the plasma much more rapidly than dAVP. The plasma concentrations of the two peptides did not decay as simple exponential functions, suggesting that both AVP and dAVP entered a slowly exchanging compartment or compartments during prolonged infusion. These differences in the metabolic clearance of AVP and dAVP may well explain the prolonged antidiuretic effect of dAVP in rats.
THE ROLE OF CORTICOSTERONE IN THE OVULATORY CYCLE OF THE HEN
Authors: SHARP P. J. , BEUVING G.
Published: December 2008

This study was undertaken in laying hens to investigate the possibility that a diurnal increase in the concentration of plasma corticosterone is directly responsible for timing the preovulatory surge of LH which results in the first egg of a sequence.

Provided that the ovary contained a mature follicle, i.m. injection of 0·5 or 2·0 but not 0·1 mg corticosterone/kg stimulated a preovulatory release of LH. The dose of 0·5 mg/kg was less effective than that of 2 mg/kg and induced release of LH in only four out of eight hens. However, it resulted in concentrations of plasma corticosterone which were outside the physiological range.

Variations in the concentrations of plasma corticosterone were measured in ten hens on two successive nights for 8·5 h starting at the onset of darkness. The birds were maintained on a lighting regimen of 14 h light/day. The hens were selected so that on the first night there was no preovulatory release of LH while on the second night there was the first preovulatory surge of LH of a sequence starting soon after the onset of darkness. No diurnal increase in the concentration of plasma corticosterone was observed during the first 6 h of darkness on either night nor was any increase seen before the preovulatory release of LH.

These observations suggest that corticosterone is not directly involved in the timing of the first preovulatory surge of LH of a sequence.
FOETAL AND MATERNAL PLASMA CONCENTRATIONS OF 13,14-DIHYDRO-15-OXO-PROSTAGLANDIN F IN THE MARE DURING LATE PREGNANCY AND AT PARTURITION
Authors: BARNES R. J. , COMLINE R. S. , JEFFCOTT L. B. , MITCHELL M. D. , ROSSDALE P. D. , SILVER M.
Published: December 2008

The concentrations of 13,14-dihydro-15-oxo-prostaglandin F (PGFM), the stable metabolite of prostaglandin F, were measured in the plasma of catheterized mares and foetuses and non-catheterized thoroughbred mares and ponies during the last months of gestation. The plasma concentration of PGFM increased gradually towards term in all groups of animals. During the operation for insertion of catheters, maternal and foetal concentrations of PGFM were high, but the values fell to basal levels 24–48 h after the operation. It was found that preoperative starvation (24 h) led to a rise in the concentration oef PGFM in th maternal plasma. The raised concentrations of PGFM during the operation were associated with low progestogen and high oestrogen concentrations in umbilical venous plasma. The subsequent survival period of the catheterized foal was inversely related to the maximum concentration of PGFM attained during the operation.

Changes in the plasma concentration of PGFM were studied during normal parturition in thoroughbred mares, during oxytocin-induced delivery in non-catheterized ponies and during premature delivery or abortion in the catheterized animals. The greatest increase in the concentration of PGFM was seen in the thoroughbred animals during second-stage labour; oxytocin also resulted in a very rapid rise in the level of PGFM, which remained high until delivery. In the catheterized animals, the birth of live foetuses was associated with a rise in the concentration of PGFM in both foetal and maternal plasma during the last 2 h before delivery. Less consistent changes were found during abortion.
INHIBIN FROM CULTURES OF RAT SEMINIFEROUS TUBULES
Authors: EDDIE L. W. , BAKER H. W. G. , DULMANIS A. , HIGGINSON R. E. , HUDSON B.
Published: December 2008

Medium from cultures of mature rat seminiferous tubules contained a substance which suppressed, in a dose-related manner, the luteinizing hormone releasing hormone (LH-RH)-stimulated secretion of FSH by cultured rat pituitary cells. The secretion of LH was suppressed to a lesser extent and the basal secretion of both LH and FSH was inconsistently affected. Gel filtration on Sephadex G-100 did not fractionate the activity. The active material did not inhibit the secretion of TSH or destroy LH-RH and the activity was not due to testosterone or oestradiol in the medium. Control media from liver cultures were inactive. It is concluded that inhibin is present in media from cultures of rat seminiferous tubules.
EFFECT OF ANAESTHESIA ON OVARIAN FOLLICULAR DEVELOPMENT AND OVULATION IN THE SHEEP SUBSEQUENT TO PROSTAGLANDIN-INDUCED LUTEOLYSIS
Authors: RADFORD H. M. , NANCARROW C. D. , FINDLAY J. K.
Published: December 2008

Prostaglandin analogues were used to induce luteal regression simultaneously in a number of ewes, thereby synchronizing the final stages of follicular maturation in these animals. Some of the ewes were anaesthetized for 24 h immediately after the injection of prostaglandin (experiment 1), and others for 15 h, starting 24 h after the injection of prostaglandin (experiment 2). In both experiments administration of anaesthetic significantly delayed the onset of oestrus and the time of ovulation relative to prostaglandin-treated control animals. The results from assays of blood samples collected at regular intervals in experiment 1 indicated that the preovulatory peak in the concentration of LH and the periovulatory changes in the concentration of FSH were similarly delayed and that during anaesthesia the level of LH was significantly reduced. It is suggested that the reduced level of LH, which probably resulted from a reduction in the secretion of releasing factor due to anaesthesia, failed to support oestrogen production by the Graafian follicle(s), thereby delaying the occurrence of oestrus and ovulation.
SPECIFIC SUPPRESSION OF FOLLICLE-STIMULATING HORMONE SECRETION IN GONADECTOMIZED MALE AND FEMALE RATS WITH INTRASPLENIC OVARIAN TRANSPLANTS
Authors: UILENBROEK J. TH. J. , TILLER R. , DE JONG F. H. , VELS F.
Published: December 2008

Adult male and female rats received an ovarian homotransplant under the kidney capsule or in the spleen 14 days after gonadectomy. After transplantation under the kidney capsule, the high levels of both LH and FSH normally observed after gonadectomy decreased to the levels found in intact male and female rats. After transplantation into the spleen, however, the serum levels of LH increased still further, although a decrease was observed in the level of FSH. In male rats, the concentrations of oestradiol-17β in the plasma increased from 17 to 56 pg/ml after transplantation of an ovary under the kidney capsule; the concentration was not increased after intrasplenic ovarian transplantation. In female rats with an intrasplenic transplant, the uterine weight did not increase and vaginal smears were not cornified. Administration of oestrogen and progesterone to produce approximately the concentrations found in rats with an intrasplenic transplant did not result in decreased concentrations of FSH. These results suggest that the ovary secretes a substance with specific FSH-suppressing activity, which is not inactivated by the liver.
EFFECTS OF AN INTRA-UTERINE DEVICE ON UTERINE CELL DIVISION AND EPITHELIAL MORPHOLOGY IN OVARIECTOMIZED MICE TREATED WITH OESTROGEN AND PROGESTERONE
Authors: MARTIN L. , FINN C. A.
Published: December 2008

Silk threads placed in the uteri of ovariectomized mice increased cell proliferation in all tissues including regions of the uterus remote from the site of insertion. Many of the effects resembled those produced by oestrogens. An intra-uterine device (IUD) increased luminal and glandular mitosis and produced various degrees of luminal epithelial hyperplasia in untreated animals. In progesterone-treated mice bearing IUD's, luminal and stromal mitosis was increased. Epithelial morphology was not affected or luminal mitosis inhibited in oestrogen-treated animals with IUD's, but stromal and glandular mitosis was increased. After combined treatment with progesterone and oestrogen, stromal mitosis was suppressed at the contact site but was increased elsewhere. Both oestrogen and progesterone suppressed the luminal leucocytosis induced by the IUD. Despite this, the IUD prevented complete progestational differentiation of the luminal epithelium and closure of the lumen. The degree to which IUD-induced abnormalities were observed depended on the hormonal status of the animal at the time of sampling.
THROMBOXANE B2 AND HUMAN PARTURITION: CONCENTRATIONS IN THE PLASMA AND PRODUCTION IN VITRO
Authors: MITCHELL M. D. , BIBBY J. G. , HICKS B. R. , REDMAN C. W. G. , ANDERSON ANNE B. M. , TURNBULL A. C.
Published: December 2008

The concentration of thromboxane B2 has been measured in the plasma of women during late pregnancy, during term and pre-term labour, in women with pre-eclampsia and in umbilical cord arterial and venous plasma. In addition, the rates of production of thromboxane B2 in vitro were determined for placental tissues obtained after spontaneous vaginal delivery or elective Caesarean section. The results obtained indicate significant differences during parturition between the sources and controlling mechanisms of thromboxane and prostaglandin production.
EFFECT OF HYPOTENSION INDUCED BY SODIUM NITROCYANOFERRATE (III) ON THE RELEASE OF ARGININE-VASOPRESSIN IN THE UNANAESTHETIZED MONKEY
Authors: FUMOUX F. , CZERNICHOW P. , ARNAULD E. , DU PONT J. , VINCENT J. D.
Published: December 2008

*I.N.S.E.R.M., U. 176, Laboratoire de Neurophysiologie, Université de Bordeaux II, F. 33076 Bordeaux Cedex, France and †I.N.S.E.R.M., U. 30, Hôpital des Enfants Malades, 149 rue de Sèvres, F. 75015 Paris, France

(Received 17 March 1978)

Haemorrhage is a potent stimulus for the liberation of arginine-vasopressin (AVP) in the unanaesthetized monkey (Arnauld, Czernichow, Fumoux & Vincent, 1977), but in contrast to results obtained with other species, the fall in arterial blood pressure seems to be a more important factor than the reduction in blood volume. However, hypotension induced by haemorrhage varies considerably from one experiment to another, irrespective of the amount of blood withdrawn. In order to control changes in arterial blood pressure more accurately and to study their effect on the release of AVP in the conscious monkey, it was decided to use infusions of sodium nitrocyanoferrate (III), a drug which is known to induce a sustained fall in arterial
EFFECTS OF THE AROMATIZATION INHIBITOR ANDROST-4-ENE-3,6,17-TRIONE ON SEXUAL DIFFERENTIATION INDUCED BY TESTOSTERONE IN THE NEONATALLY CASTRATED RAT
Authors: BOOTH JANET E.
Published: December 2008

Groups of rats were castrated on the day of birth (day 1) and injected with testosterone, androst-4-ene-3,6,17-trione (ADT, an inhibitor of aromatization), testosterone + ADT or oil daily from day 1 to day 5. The aromatizable androgen testosterone suppressed both cyclic gonadotrophin secretion, as judged from the absence of corpora lutea in grafted ovaries, and the behavioural response to injections of oestradiol benzoate and progesterone in adulthood. It also stimulated normal development of the penis and ejaculation in behaviour tests carried out after injections of testosterone propionate. The aromatization inhibitor ADT, like oil, did not affect either cyclic gonadotrophin secretion or receptive behaviour, but injections of ADT given at the same time as testosterone significantly reduced the effects of the androgen on both cyclic gonadotrophin secretion and receptive behaviour. Although neonatal administration of ADT did not affect the testosterone-stimulated development of the penis or the ability of the rats to achieve penile intromissions, it did interfere with ejaculation. None of the rats which had been injected with testosterone+ADT ejaculated. These results support the concept that during infancy neural conversion of androgens to oestrogens is important both for the suppression of the female patterns of gonadotrophin secretion and sexual behaviour and for the central organization of normal patterns of male sexual behaviour. Normal completion of the differentiation of the male genital tract appears to be independent of the central organization of masculine patterns of sexual behaviour.
ANTIANDROGENIC EFFECTS OF THE PINEAL GLAND AND MELATONIN IN CASTRATED AND INTACT PREPUBERTAL MALE RATS
Authors: ALONSO R. , PRIETO L. , HERNANDEZ C. , MAS M.
Published: December 2008

In castrated prepubertal rats, pinealectomy enhanced the testosterone-induced growth response of the seminal vesicles and melatonin inhibited this effect in a dose-related manner. In entire animals, the serum concentration of LH was increased after pinealectomy with no significant changes in other parameters. Administration of melatonin to intact, pinealectomized rats did not affect the serum concentrations of LH or testosterone but caused a doserelated decrease in the weight of the seminal vesicles. The highest dose of melatonin tested reduced the weight of the ventral prostate gland and the uptake of radioactivity by both the ventral prostate gland and the testes after injection of [5-3H]uridine. It is suggested that the pineal gland and melatonin may exert an antagonistic effect on the biological activity of androgens administered to castrated rats and that melatonin can reduce the growth of the accessory sex organs of intact, pinealectomized rats, in spite of a high concentration of LH in the serum. The well-known inhibitory influence of systemically administered melatonin on the accessory sex organs in male rats may be due to its antagonistic effect at a peripheral level.
PRODUCTION OF THROMBOXANE B2 BY INTRA-UTERINE TISSUES FROM LATE PREGNANT RHESUS MONKEYS (MACACA MULATTA) IN VITRO
Authors: MITCHELL M. D. , HICKS B. R. , THORBURN G. D. , ROBINSON J. S.
Published: December 2008

The rates of production of thromboxane B2 in vitro by intra-uterine tissues obtained from late pregnant monkeys by Caesarean section have been determined. The general quantitative order of rates of production was decidua basalis = decidua parietalis > placenta > chorion > amnion = myometrium. Myometrial production of thromboxane B2 was greater at term than during late pregnancy; no other tissue showed a significant trend with advancing gestation. These data demonstrate that the production of thromboxane B2 by intra-uterine tissues from late pregnant monkeys is both qualitatively and quantitatively different from the production of prostaglandins described previously. It is suggested that prostaglandins rather than thromboxanes are more intimately involved in the onset of labour in the rhesus monkey.
MAINTENANCE OF FUNCTIONING HUMAN PITUITARY TUMOURS IN 'NUDE' ATHYMIC MICE
Authors: O'SULLIVAN J. P. , ALEXANDER K. M. , JENKINS J. S.
Published: December 2008

Departments of Medicine and Histopathology, St George's Hospital Medical School, Cranmer Terrace, London, SW17 ORE

(Received 4 May 1978)

There are now many reports of the growth of various human malignant tumours such as colonic carcinoma and malignant melanoma in the 'nude' athymic mouse (Rygaard & Povlsen, 1969), but there are few instances of human benign tumours being transplanted successfully into these animals. Nevertheless, the possibility of using the 'nude' athymic mouse as a vehicle for maintaining pituitary adenomatous tissue in a viable state for a prolonged period under conditions which are more physiological than those of tissue culture has been examined.

Pituitary adenomas were obtained from seven patients undergoing craniotomy for the treatment of acromegaly and from three patients without acromegaly where the tumour was removed because of visual impairment. Part of the tissue was fixed in formol–saline for light microscopy, part was fixed in 4% glutaraldehyde in phosphate
CONCENTRATIONS OF HYDROGEN IONS, OXYGEN, CARBON DIOXIDE AND BICARBONATE IN PORCINE FOLLICULAR FLUID
Authors: KNUDSEN J. F. , LITKOWSKI L. J. , WILSON T. L. , GUTHRIE H. D. , BATTA S. K.
Published: December 2008

Department of Physiology and * Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland 21201, U.S.A. and †The United States Department of Agriculture, Beltsville, Maryland 20705, U.S.A.

(Received 26 June 1978)

The chemical composition of human ovarian follicular fluid has been well characterized (Shalgi, Kraicer & Soferman, 1972; Edwards, 1974). However, compositional studies of porcine follicular fluid (PFF; Schuetz, 1974; Chang, Jones, Ellefson & Ryan, 1976), have not included acid–base measurements (pH, oxygen and carbon dioxide tension (Po2, Pco2), concentration of bicarbonate HCO3−]). Recent studies of the nuclear maturation of porcine oocytes have demonstrated a rate of maturation of only 55–80% for oocytes collected from ovaries obtained at the abattoir (Tsafriri & Channing, 1975) and it was suggested that maturing and non-maturing oocytes may have undergone nuclear degeneration. It has also been shown in monkeys that oocytes which appear mature when examined by light microscopy may in fact
FEEDBACK CONTROL BY THE TESTIS OF GONADOTROPHIN SECRETION: AN EXAMINATION OF THE INHIBIN HYPOTHESIS
Authors: MAIN S. J. , DAVIES R. V. , SETCHELL B. P.
Published: December 2008

Spermatogenesis in rats was interrupted by local X-irradiation, heat or ligation of the testicular efferent ducts. A significant and specific rise in the serum level of FSH occurred 5–8 days after ligation of the efferent ducts, reaching twice the value observed in shamoperated controls by 21 days after the operation. After the testes were heated to 43 °C for 30 min, the serum levels of both LH and FSH were raised within 3 days and remained so up to 50 days after treatment. After X-irradiation, no changes in the concentration of FSH were observed in the first 21 days after treatment, but the serum levels of both gonadotrophins were increased at 49 days. By comparing the relative increases in the concentrations of FSH and LH after germ cell damage with those occurring after castration, it was evident that testicular androgens could account for only part of the normal feedback control of FSH secretion; at least one third of the inhibition of FSH secretion appeared to be due to non-androgenic sources, presumably 'inhibin'.
INTRA-OVARIAN FORMATION OF STEROID SULPHATES: MEASUREMENT AND INFLUENCE OF GONADOTROPHINS
Authors: STURM GERHARD , HANNAPPEL ELISABETH
Published: December 2008

The steroid sulphokinase activity in 105 000 g supernatant fractions from rat and bovine ovarian tissue has been determined by measuring the radioactivity incorporated into conjugated steroids after incubation with 14C-labelled androgens and oestrogens. The enzyme from bovine ovaries was partially characterized, changes in its activity with pH were measured and Km values of 30, 10 and 4 μmol/l were obtained for testosterone, oestradiol and oestrone respectively. The rate of formation of sulphates from oestrogens by preparations of bovine luteal tissue was 10–20 times higher than the rate of formation by follicular tissue (P< 0·001), but both tissues exhibited similar rates of sulphate formation with testosterone. Sulphation of dehydroepiandrosterone by the ovaries of gonadotrophin-treated rats did not differ from that observed in the control group, whereas sulphation of oestrone was nearly three times greater in ovaries obtained from rats treated with gonadotrophins (P< 0·005). Furthermore, a comparison of steroid sulphation in the ovaries of pseudopregnant and normal cyclic rats showed that the sulphation of oestrone was about six times greater during pseudopregnancy. These observations suggest that the formation of oestrogen, but not androgen, sulphates by ovarian aryl sulphokinase differs in follicular and luteal tissue and may be gonadotrophin dependent. The greater capacity of luteal, compared with follicular, tissue for the sulphation of oestrogens may be a control mechanism for steroidogenesis within the ovarian tissue.
CYTOLOGICAL EFFECTS OF HORMONES AND PLASMA ON BOVINE MAMMARY TISSUE IN VITRO
Authors: NICKERSON S. C. , HEALD C. W. , BIBB T. L. , McGILLIARD M. L.
Published: December 2008

Mammary explants from two heifers pretreated with oestradiol and progesterone were cultured for 96 h with various combinations of hormones and calf plasma to identify the complement causing mammary tissue development in vitro in the cow. Initial tissue histology, determined by quantitative morphological analysis, was maintained by incubation with insulin, cortisol, oestrogen and progesterone; enlarged lumina were observed after treatment with insulin and cortisol. Lactogenesis was induced in vitro by insulin, cortisol and prolactin, enhanced by adding oestrogen and progesterone at the doses used here and further stimulated by the addition of plasma. The most highly developed mammary alveoli were characterized by an increased luminal area with lipid and stainable secretion, epithelia with large lipid droplets in the apical cytoplasm and a limited stromal area. In a second experiment, samples of plasma were collected from two cows, successfully induced to lactate, on days 6, 15, 17, 19 and 21 after treatment with oestradiol and progesterone. Mammary gland explants from five heifers pretreated with oestradiol and progesterone in vivo were cultured with insulin and cortisol plus these plasma samples (30%, v/v) to test for changes in lactogenic activity. All plasma samples were found equally beneficial in promoting tissue differentiation. These experiments show that low concentrations of ovarian steroids synergize with prolactin at the level of the mammary epithelium and suggest that other plasma components aid the development of bovine mammary epithelium in vitro.
OVARIAN DEPENDENCE OF THE STIMULATORY EFFECT OF NEONATAL HORMONE TREATMENT ON PLASMA LEVELS OF PROLACTIN IN FEMALE MICE
Authors: NAGASAWA H. , YANAI REIKO , JONES L. A. , BERN H. A. , MILLS KAREN T.
Published: December 2008

Pharmacology Division, National Cancer Center Research Institute, Tsukiji 5-1-1, Chuo-ku, Tokyo 104, Japan and *Department of Zoology and Cancer Research Laboratory, University of California, Berkeley, California 94720, U.S.A.

(Received 24 April 1978)

Recent studies have demonstrated that neonatal exposure of female mice to oestradiol-17β, testosterone, diethylstilboestrol and 5β-dihydrotestosterone results in increased plasma levels of prolactin in animals as old as 15 months (Yanai, Mori & Nagasawa, 1977; Nagasawa, Mori, Yanai, Bern & Mills, 1978). Treatment with these hormones (Mori, Bern, Mills & Young, 1976; Jones & Bern, 1977; Nagawasa et al. 1978) or with progesterone (Jones & Bern, 1977; Jones, Bern & Wong, 1977) also results in normal and neoplastic stimulation of the mammary gland, which is dependent on the presence of the ovaries. The present communication provides data on plasma levels of prolactin in old female mice treated neonatally with oestradiol or progesterone or both steroids and the effects
CONCENTRATIONS OF 6-OXO-PROSTAGLANDIN F1α AND THROMBOXANE B2 IN THE TRACHEAL FLUID OF FOETAL SHEEP
Authors: MITCHELL M. D. , ROBINSON J. S.
Published: December 2008

Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU

(Received 21 July 1978)

Prostaglandins of the E and F series have been shown to relax or contract respectively guinea-pig trachea and recently it has been demonstrated that the prostaglandin endoperoxides PGG2 and PGH2 (immediate precursors of prostaglandins E and F) have far greater potency in contracting tracheal smooth muscle than prostaglandin F (Hamberg, Svensson, Hedqvist, Strandberg & Samuelsson, 1976). Furthermore, both thromboxane A2 and prostacyclin can also elicit contraction of the trachea with thromboxane A2 being considerably more active (Omini, Moncada & Vane, 1977; Svensson, Strandberg, Tuvemo & Hamberg, 1977). Administration of thromboxane A2 has been shown to raise the tracheal insufflation pressure in guinea-pigs (Svensson et al. 1977) and indeed its stable metabolite thromboxane B2 is released in relatively large amounts from sensitized guinea-pig lungs when challenged with antigen (Dawson, Boot, Cockerill,
DIFFERENTIAL EFFECTS OF OESTRADIOL AND ETHYNYL OESTRADIOL ON LIPID METABOLISM IN THE FEMALE RAT
Authors: VALETTE A. , CARASCO G. , VÉRINE A. , VARÉSI L. , BOYER J.
Published: December 2008

Service d'Explorations Métaboliques, Hôpital de la Conception, 13385 Marseille Cedex 4, France

(Received 24 July 1978)

It has recently been shown that ethynyl oestradiol markedly decreases lipase activity in the liver (Valette, Verine, Salers & Boyer, 1977). These observations, along with reports of oestrogen receptors in the liver (Chamness, Costlow & McGuire, 1975) suggest that oestrogens exert considerable influence over the hepatic metabolism of lipids. Previous investigations (DeLorimier, Gordon, Lowe & Carbone, 1965; Gallagher, Mueller & Kappas, 1966) have suggested that the extent of the hepatic changes could be correlated with the molecular nature of the hormonal compound and might depend particularly on the 17α-alkyl-substituted group in synthetic oestrogens. The influence of the ethynyl function in the 17α-position of oestradiol-17β on the oestrogen-induced changes observed in hepatic lipases and serum levels of triglycerides has therefore been examined.

Adult female Sprague–Dawley rats (220–240 g) were allowed free access to food and