bluuebunny/crossref_metadata_2025_split huggingface dataset:
UPTAKE AND BINDING OF GLUCOCORTICOIDS IN FISH TISSUES
Authors: PORTHÉ-NIBELLE JACQUELINE , LAHLOU BRAHIM 
Published: December 2008

Cytosols prepared from the liver and various tissues of goldfish (intact or hypophysectomized) and trout (intact) were incubated at 2 °C in the presence of tritiated cortisol or dexamethasone (3 × 10−9 to 3 × 10−6 mol/l) with or without a 1000-fold excess of unlabelled steroid. In contrast to mammals, the specifically bound component represented a very low fraction of the total bound steroid retained on DEAE cellulose filters and did not show saturation over a large range of concentrations.
The subcellular distribution of [3H]dexamethasone was studied in trout liver after intravascular injection of the labelled steroid with and without an excess of unlabelled steroid.
The amount of protein-bound steroid in the cytosol again corresponded to a small (4%) proportion of the free steroid. The large reduction in the uptake of tritiated dexamethasone, which was induced in both the cytosol and nuclei by competing unlabelled dexamethasone, was interpreted as evidence for mediated entry across cellular and nuclear membranes.
These results indicate that high-affinity binding sites are absent, or present only in very small numbers in cytosol from teleost tissues. The entry of glucocorticoids into the nucleus may not require the hormone to be bound to high-affinity cytosolic receptors unless the binding, though quantitatively small, displays a high rate of turnover.
FAILURE OF SODIUM LOADING TO INFLUENCE THE CONCENTRATION OF ISO-RENIN IN RAT BRAIN
Authors: HUSAIN A. , JONES C. W. , DAY M. D. 
Published: December 2008

Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Clifton Boulevard, Nottingham, NG7 2UH
(Received 23 February 1978)
In addition to its well-known peripheral actions, angiotensin II has been implicated in central nervous mechanisms concerned with the modulation of blood pressure, drinking, the release of antidiuretic hormone (ADH) and the secretion of adrenocorticotrophin (ACTH; see Severs & Daniels-Severs, 1973). The receptors responsible for mediating these central effects are both central and peripheral in relation to the blood–brain barrier. Because angiotensin II does not cross this barrier rapidly (Volicier & Loew, 1971), the physiological significance of the receptive sites for angiotensin II which lie on the central side of the barrier (e.g. in the mid-brain peri-aqueductal grey matter and the supraoptic nucleus of the hypothalamus) is unclear.
Recently, an independent iso-renin-angiotensin system has been demonstrated in the central nervous system (for review see Ganten, Hutchinson, Schelling, Ganten & Fisher, 1976)
MATURATIONAL CHANGES IN THE CHARACTERISTICS OF OESTROGEN-INDUCED SURGES OF LUTEINIZING HORMONE IN IMMATURE DOMESTIC GILTS
Authors: ELSAESSER F. , FOXCROFT G. R. 
Published: December 2008

Institute für Tierzucht und Tierverhalten, FAL, Mariensee, 3057 Neustadt 1, Federal Republic of Germany and * PES-Animal Physiology, University of Nottingham, School of Agriculture, Sutton Bonington, Loughborough, LE12 5RD
(Received 19 April 1978)
Possible causes of the variability in oestrogen-induced surges of luteinizing hormone (LH) in prepubertal miniature (Elsaesser, Parvizi & Ellendorff, 1978) and domestic (Foxcroft, 1978) gilts have been investigated.
Four groups of six German Landrace gilts with indwelling jugular cannulae were kept under conditions of natural daylight. Groups A and C (60 and 161 days old respectively) received 60 μg oestradiol benzoate (OB)/kg body weight (Progynon Oleosum, Schering); groups and D (60 and 161 days) received 600 μg/kg body weight. Concentrations of OB (Elsaesser et al. 1978) and LH (Foxcroft, Pomerantz & Nalbandov, 1975) were determined in plasma samples taken at least every 12 and 4h, respectively, for 79·5 h after the i.m. injection of oil and for
INHIBITION OF GONADOTROPHIN SECRETION BY INDUCED HYPERPROLACTINAEMIA IN THE MALE RAT
Authors: McNEILLY A. S. , SHARPE R. M. , DAVIDSON D. W. , FRASER H. M. 
Published: December 2008

Pituitary glands were transplanted under the kidney capsule to induce hyperprolactinaemia in both immature (41 days old) and adult (150 days old) intact male rats. Blood samples were taken for hormone analysis at regular intervals after transplantation and the animals were killed 42–45 days after the operation.
Serum levels of prolactin rose in all groups of rats with transplants except in those animals bearing only one pituitary gland. Increased adrenal weight in all transplanted groups suggested that effective hyperprolactinaemia was always achieved. Serum levels of LH and FSH were significantly suppressed in all animals with transplants; the pituitary LH content was as reduced in all animals except those bearing one pituitary transplant but reductions in the pituitary FSH content were inconsistent. Although the amount of luteinizing hormone releasing hormone (LH-RH) in the hypothalamus did not differ significantly between groups, the effects of hyperprolactinaemia on serum and pituitary levels of LH and FSH suggested a functional lack of LH-RH (possibly due to an increase in the sensitivity of the hypothalamus to the negative feedback effects of testicular steroids).
Serum levels of testosterone remained normal in spite of reductions in the serum concentrations of LH and FSH and, in immature animals, a reduction in testicular binding of LH/human chorionic gonadotrophin.
These results are discussed in the light of previous conflicting reports on the effects of induced hyperprolactinaemia on the regulation of secretion of LH and FSH.
SEXUAL DIFFERENCE IN THE EFFECT OF CYPROTERONE ACETATE AND GLUCOCORTICOIDS ON α2u-GLOBULIN IN GONADECTOMIZED RATS
Authors: VANDOREN G. , HEYNS W. , VERHOEVEN G. , DE MOOR P. 
Published: December 2008

Laboratorium voor Experiméntele Geneeskunde, Katholieke Universiteit Leuven, Rega Instituut, Minderbroedersstraat 10, B-3000 Leuven, Belgium
(Received 28 March 1978)
The synthesis of α2u-globulin, the major protein found in the urine of adult male rats (Roy & Neuhaus, 1966; Roy, Neuhaus & Harmison, 1966), is controlled by several hormones. Androgens, growth hormone, thyroxine and glucocorticoids promote the synthesis of this protein, whereas oestrogens and a factor secreted by ectopically transplanted pituitary glands suppress it (Roy & Neuhaus, 1967; Roy, 1973; Kurtz, Sippel & Feigelson, 1976; Vandoren, Van Baelen, Verhoeven & De Moor, 1978). Cyproterone acetate (CA), a potent antiandrogen, inhibits the androgenic induction of α2u-globulin in ovariectomized rats, but does not suppress its synthesis in intact male rats (Roy, 1976). In the present experiments, the influence of CA on the induction of α2u-globulin by testosterone propionate (TP) in the serum of gonadectomized male and female rats was compared. Evidence is presented for
EFFECT OF RESERPINE ON PLASMA CONCENTRATIONS OF GROWTH HORMONE AND PROLACTIN IN THE DOMESTIC FOWL
Authors: HARVEY S. , SCANES C. G. , CHADWICK A. , BOLTON N. J. 
Published: December 2008

Department of Zoology, University of Hull, Hull, HU6 7RX, * Department of Physiology, Rutgers University, New Brunswick, New Jersey 08903, U.S.A. and †Department of Pure and Applied Zoology, University of Leeds, Leeds, LS2 9JT
(Received 9 June 1978)
It has been established that biogenic amines are involved in control of the secretion of prolactin (MacLeod, 1976) and growth hormone (GH; Martin, 1976) in mammals. In birds there is very little evidence for this, although in the domestic fowl it has recently been demonstrated that sytemically administered catecholamines (adrenaline and noradrenaline) markedly lower the concentration of GH in the peripheral plasma (Harvey & Scanes, 1978) and that serotonin stimulates the release of prolactin from incubated hemipituitary glands (Border & Chadwick, 1977). Therefore, to elucidate further the possible involvement of biogenic amines in the regulation of GH and prolactin secretion, the effect of reserpine (a 5-hydroxytryptamine- and catecholamine-depleting agent) on the concentrations
STEROIDAL CONTROL OF THE RELEASE OF THE PREOVULATORY SURGE OF LUTEINIZING HORMONE IN THE RAT
Authors: WILSON CATHERINE A. , HADLEY J. C. , GILBERT D. , McNEILLY A. S. 
Published: December 2008

Experiments were carried out on 4 day cyclic rats or immature rats induced to ovulate by administration of pregnant mare serum gonadotrophin. Removal of the ovaries and adrenal glands at 17.00 h of pro-oestrus, i.e. after the critical period, prevented the appearance of the surge of LH. Sham-operation or removal of only one of the sets of glands had no effect. This indicates that the preovulatory increase in the concentration of oestradiol is not solely responsible for the surge of LH; the presence of a steroid, secreted by the ovaries and adrenal glands in the late afternoon of pro-oestrus, is also required.
Attempts were made to reinstate the surge of LH in ovariectomized, adrenalectomized rats by administration of one of the steroids normally secreted in late pro-oestrus. Corticosterone, 20α- and 20β-hydroxy-4-pregnen-3-one and 17α-hydroxyprogesterone all had no effect. Progesterone injected at the time of the operation stimulated the release of LH but only after the plasma concentration had reached its maximum 3–5 h after injection. Testosterone also stimulated the release of LH some hours after administration.
POSSIBLE NEONATAL IMPRINTING OF LUTEINIZING HORMONE FEEDBACK BY TESTOSTERONE IN MALE RATS
Authors: BERAUD G. , AUDRAIN M. 
Published: December 2008

Université de Rennes, Laboratoire de Physiologie des Régulations, UER des Sciences Biologiques, 35031 Rennes Cedex, France
(Received 3 May 1978)
The results described by Naftolin, Ryan, Davies, Reddy, Flores, Petro, White, Takaoka & Wolin (1975) and Moguilevsky, Scacchi & Rubinstein (1977) indicate that the aromatization of androgens to oestrogens during the neonatal period provides a probable route of action for the testicular androgens. It is also thought that during this critical period, the conversion of androgens to oestrogens is involved in regulation of the hepatic and adrenal enzymes that metabolize steroid hormones (De Moor, Verhoeven & Heyns, 1973; Goldman, Gustafsson & Stenberg, 1974; Gustafsson & Stenberg, 1974). There is considerable evidence that androgens inhibit the secretion of luteinizing hormone (LH) when administered to immature and mature male rats immediately after castration (Mahesh, Muldoon, Eldridge & Korach, 1975; Moger, 1976; Shin & Howitt, 1976). The purpose of the present investigation was
DIRECT ANTIPROLIFERATIVE EFFECT OF DOPAMINE AGONISTS ON THE ANTERIOR PITUITARY GLAND IN ORGAN CULTURE
Authors: PAWLIKOWSKI M. , KUNERT-RADEK J. , STĘPIEŃ H. 
Published: December 2008

Department of Experimental Endocrinology, Institute of Endocrinology, Medical Academy of Łódź, Dr Sterling sir. 3, 91–425 Łódź, Poland
(Received 22 May 1978)
Lloyd, Meares & Jacobi (1975) observed inhibition of mitotic activity in the anterior pituitary gland by the dopamine receptor agonist, bromocriptine, in oestrogen-treated male rats. This observation has been confirmed in our laboratory (Stępień, Wolaniuk & Pawlikowski, 1978). Suppression of mitotic activity in the pars intermedia of the rat pituitary gland by bromocriptine has also been observed (Rychter & Stępień, 1977). Furthermore, it has been found that the dopamine receptor blocker, pimozide, enhances mitotic activity in the rat anterior pituitary gland (Stępień et al. 1978). By the use of various ergot alkaloids, MacLeod & Lehmeyer (1973) succeeded in inhibiting the growth of transplantable rat pituitary tumours. There have also been observations suggesting an antiproliferative effect of bromocriptine on human pituitary tumours (Wass, Thorner, Morris, Rees, Mason, Jones &
EFFECT OF LUTEINIZING HORMONE ON THE CONCENTRATION OF CYCLIC GMP IN RABBIT OVARIES
Authors: PATWARDHAN V. V. , LANTHIER A. 
Published: December 2008

Laboratoire d'Endocrinologie, Hôpital Notre-Dame et Département de Medicine, Université de Montréal, Montréal, Canada
(Received 28 June 1978)
Cyclic AMP has been implicated as an intermediate in some of the actions of luteinizing hormone (LH) on ovarian tissues, such as stimulation of steroidogenesis (LeMaire & Marsh, 1975). Both in vitro (Marsh, Butcher, Savard & Sutherland, 1966) and in vivo (Armstrong, Dorrington & Robinson, 1976), stimulation with LH results in a rapid increase in the amount of cyclic AMP in ovarian tissues, which precedes the LH-induced increase in steroidogenesis. Recently, studies on rat ovaries (Grinwich, Ham, Hichens & Behrman, 1976; Ratner, 1976; Ratner & Sanborn, 1976) have indicated that the ovarian tissue content of cyclic GMP may also be regulated by LH, but in a direction opposite to that of cyclic AMP. In the rabbit, Goff & Major (1975) have shown that administration of human chorionic gonadotrophin (HCG) causes a biphasic increase
EFFECT OF NEONATAL ANDROGEN TREATMENT AND ORCHIDECTOMY ON PITUITARY LEVELS OF GROWTH HORMONE IN THE RAT
Authors: SOMANA REON , VISESSUWAN SERMSRI , SAMRIDTONG AYUDHYA , HOLLAND R. C. 
Published: December 2008

Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, Thailand
(Received 19 July 1978)
Sex hormones have been shown to influence the levels of growth hormone (GH) in rats and mice (Birge, Peake, Mariz & Daughaday, 1967; Callahan, Somana & Srikhao, 1972; Sinha, Selby, Lewis & VanderLaan, 1972). Since treatment of neonatal female rats with androgens changes the pattern of gonadotrophin secretion from the cyclic female type to the non-cyclic male type (Gorski, 1971; Dorner, 1977), it was thought to be of interest to discover whether this treatment alters the pituitary GH content in female rats to levels similar to those found in male rats before and after puberty and whether after neonatal orchidectomy there is a reduction in the pituitary GH content to levels found in normal female rats.
Newborn rats of a Fisher strain were divided into four groups: normal male, orchidectomized male and normal
ABILITY OF MOLAR TROPHOBLASTS TO SPLIT THE SIDE-CHAIN OF [26-14C]CHOLESTEROL IN VITRO
Authors: GUNASEGARAM R. , PEH K. L. , CHEW P. C. T. , KARIM S. M. M. , RATNAM S. S. 
Published: December 2008

University Department of Obstetrics and Gynaecology, Kandang Kerbau Hospital for Women, Singapore 8, Republic of Singapore
(Revised manuscript received 1 September 1978)
Evidence from various laboratories indicates that molar trophoblasts may be biosynthetically very active in vitro and capable of bringing about several steroidal transformations (Van Leusden & Siemerink, 1969; Coutts & MacNaughton, 1971). However, a lack of incorporation of labelled acetate into pregnenolone and progesterone by molar vesicles has been observed by Van Leusden (1971) and Van Leusden & Villee (1966). Van Leusden (1971) also failed to demonstrate the conversion of [5-3H]mevalonate into sterols, cholesterol and steroids by these vesicles. These observations could be interpreted as indicating that the molar vesicles lack or possess only a very limited capacity to biosynthesize cholesterol from acetate and mevalonate. There also remains the distinct possibility that the vesicles are deficient in the C-20,22-desmolase complex that cleaves the sterol molecule into pregnenolone and
RELATIVE ACTIVITY, PLASMA ELIMINATION AND TISSUE DEGRADATION OF SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE AND CERTAIN OF ITS ANALOGUES
Authors: SWIFT A. D. , CRIGHTON D. B. 
Published: December 2008

The abilities of three nonapeptide analogues of synthetic luteinizing hormone releasing hormone (LH-RH) to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in anoestrous and cyclic ewes were examined, as were their elimination from the plasma in vivo and degradation by extracts of the hypothalamus, anterior pituitary gland, lung, kidney, liver and plasma in vitro. In all cases, comparisons were made with synthetic LH-RH.
When injected i.v. into mature ewes as a single dose, the potencies of the analogues were graded and Des Gly-NH210 LH-RH ethylamide was found to be the least potent. It was not possible to demonstrate any significant increase in the potency of this analogue over LH-RH, although a trend was apparent with each parameter examined. [d-Ser(But)6] Des Gly-NH210 LH-RH ethylamide had the greatest potency. There were no differences between the responses of anoestrous ewes and those of ewes treated on day 10 of the oestrous cycle. None of the analogues had a rate of elimination from the plasma different from that of LH-RH during either the first or the second components of the biphasic disappearance curve.
The incubation of LH-RH with tissue extracts showed that extracts of the hypothalamus and anterior pituitary gland degraded LH-RH to a similar extent. Both the hypothalamic and anterior pituitary gland extracts degraded more LH-RH than did lung extract, which in turn destroyed more LH-RH than did extracts of kidney or liver tissue. The degradative abilities of kidney and liver extracts did not differ from each other. Plasma failed to degrade LH-RH or the analogues. Although LH-RH was rapidly destroyed by hypothalamic extract in vitro, of the analogues, only Des Gly-NH210 LH-RH ethylamide was degraded. The anterior pituitary gland and kidney extracts failed to degrade [d-Ser6] Des Gly-NH210 LH-RH ethylamide and [d-Ser(But)6] Des Gly-NH210 LH-RH ethylamide as rapidly as LH-RH. Extracts of liver and lung were incapable of catabolizing any of the analogues.
There was an inverse correlation between the LH- and FSH-releasing potency of an analogue and its rate of degradation by anterior pituitary gland extract. The slower rates of catabolism of certain analogues of LH-RH by the anterior pituitary gland may explain their increased LH- and FSH-releasing potency.
MORPHOLOGICAL CHANGES IN THE ENDOCRINE PANCREAS IN PREGNANT RATS WITH EXPERIMENTAL DIABETES
Authors: VAN ASSCHE F. A. , AERTS L. , GEPTS W. 
Published: December 2008

This present study has demonstrated that during normal pregnancy in the rat the number of β-cells is increased (hyperplasia) and the volume of the individual β-cells is increased (hypertrophy).
During experimental diabetes, however, the endocrine pancreas has an impaired capacity to compensate during pregnancy. In the experimental diabetic pregnant rat the β-cells cannot replicate due to the unfavourable metabolic environment. This could reflect the complications caused by diabetes during human pregnancy.
TESTOSTERONE 5α-REDUCTASE ACTIVITY AS RELATED TO PROLIFERATIVE STATUS IN MOUSE ACCESSORY SEX GLANDS
Authors: ALISON M. R. , WRIGHT N. A. 
Published: December 2008

Testosterone 5α-reductase activity has been measured during the proliferative response of the seminal vesicle and coagulating gland of the castrated mouse after continuous treatment with testosterone. Daily subcutaneous injections were begun either 3 or 14 days after castration. At 3 days after castration, a pre-replicative period of 50–60 h occurred before the onset of DNA synthesis, and a continuous [3H]thymidine labelling procedure revealed that only a minority of epithelial cells were subsequently involved in the transitory proliferative response. At 14 days after castration, cells were able to prepare more quickly for DNA synthesis (20–30 h), and the subsequent proliferative response involved a higher proportion of the epithelial cells present.
At 14 days after castration, testosterone treatment resulted in the activity of the enzyme/ mg homogenate increasing fourfold in the seminal vesicle and tenfold in the coagulating gland, to values almost double those of control (intact animals. At 3 days after castration, testosterone treatment resulted in much slower increases in enzyme activity, and at the completion of day 5 of treatment, levels were close to control values. It is concluded that a relationship may exist between the initial increase in 5α-reductase activity and the duration of the pre-replicative period before DNA synthesis begins. Although testosterone and its resultant effects upon 5α-reductase activity are clearly implicated in the genesis of the proliferative response, the ultimate control of cell proliferation must be independent of androgenic hormones. When cell division was effectively curtailed at the completion of day 4 of testosterone treatment, abnormally high levels of enzyme activity were still present.
PROLONGED RELEASE BY DIOESTROUS RATS OF FOLLICLE-STIMULATING HORMONE DURING THE PERIOD OF OVULATION INDUCED BY LUTEINIZING HORMONE RELEASING HORMONE
Authors: SASAMOTO SHUJI , HARADA SHIGEO , TAYA KAZUYOSHI 
Published: December 2008

When 1·0 μg luteinizing hormone releasing hormone (LH-RH) was given i.v. three times at 1 h intervals from 17.00 to 19.00 h on the day of dioestrus (day 0) to regular 4 day cyclic rats, premature ovulation was induced the next morning (day 1) with the number of ova present comparable to normal spontaneous ovulation. The next spontaneous ovulation occurred on the morning of day 5, 4 days after premature ovulation induced by LH-RH.
Plasma concentrations of FSH and LH showed transient rises and falls within 1 h of administration of LH-RH; concentrations of FSH in the plasma decreased from 20.00 h on day 0 but markedly increased again from 23.00 h on day 0 to 02.00 h on day 1 and these high levels persisted until 14.00 h on day 1, with only a small increase of plasma LH during this period. The duration of increased FSH release during premature ovulation induced by LH-RH treatment was 6 h longer than the FSH surge occurring after administration of HCG on day 0. Surges of gonadotrophin were absent on the afternoon of day 1 (the expected day of pro-oestrus) and the surges characteristic of pro-oestrus occurred on the afternoon of day 4 and ovulation followed the next morning. The pituitary content of FSH did not decrease despite persisting high plasma levels of FSH during premature ovulation induced by either LH-RH or HCG on day 0.
The changes in uterine weight indicated that the pattern of oestrogen secretion from the day of premature ovulation induced by LH-RH to the day of the next spontaneous ovulation was similar to that of the normal 4 day oestrous cycle. When 10 i.u. HCG were given on day 0, an increase in oestrogen secretion occurred on day 2, 1 day earlier than in the group given LH-RH on day 0. This advancement of oestrogen secretion was assumed to be responsible for the gonadotrophin surges on day 3.
Similar numbers of fully developed follicles were found by 17.00 h on day 2 after premature ovulation induced by either LH-RH or HCG, suggesting that the shorter surge of FSH during premature ovulation induced by HCG had no serious consequences on the initiation of follicular maturation for the succeeding oestrous cycle in these rats.
Administration of LH-RH on day 0 had no direct effect on the FSH surge during premature ovulation. Secretory changes in the ovary during ovulation may be responsible for this prolonged selective release of FSH.
PLASMA TESTOSTERONE LEVELS IN INTACT AND HEMICASTRATED GROWING COCKERELS
Authors: DRIOT F. J. M. , DE REVIERS M. , WILLIAMS J. 
Published: December 2008

Changes in the levels of testosterone in plasma were measured by radioimmunoassay in blood samples taken at frequent intervals between 2 and 26 weeks of age from entire cockerels and cockerels hemicastrated before 2 weeks of age. In both groups the pattern of testosterone secretion could be divided into three clearly defined phases. In young birds, the levels of testosterone in plasma were low (0·3 ng/ml) but in the prepubertal period, at 11 weeks of age, they started to rise and continued to rise until 22 weeks of age when adult levels, which fluctuated between 2·5 and 3·5 ng/ml, were reached. In the immediate period after hemicastration, the concentration of testosterone decreased temporarily. From 11 weeks of age the levels of testosterone in the hemicastrated birds were approximately 75% of those in intact birds.
These results are discussed in relation to the compensatory testicular hypertrophy which occurs in growing cockerels hemicastrated at an early age.