bluuebunny/crossref_metadata_2025_split huggingface dataset:
EARLY INCREASES IN RIBONUCLEIC ACID POLYMERASE ACTIVITIES OF DIMETHYLBENZANTHRACENE-INDUCED MAMMARY TUMOUR NUCLEI IN RESPONSE TO OESTRADIOL-17β AND TAMOXIFEN
Authors: NICHOLSON R. I. , DAVIES P. , GRIFFITHS K. 
Published: December 2008

SUMMARY
Studies on the mode of action of tamoxifen have shown that this compound ultimately causes regression of mammary tumours induced in female rats by 7,12-dimethylbenz(a)-anthracene, but induces preliminary effects similar to those produced by oestradiol-17β. Following a single intravenous injection of either substance, a sequence of events was observed which included depletion of cytoplasmic receptor, a concomitant increase in nuclear receptor and a subsequent replenishment of cytoplasmic receptor. Tamoxifen and oestradiol-17β induced a transient increase in RNA polymerase B activity, followed by increases in RNA polymerase A and, again, RNA polymerase B activity. Tamoxifen, unlike oestradiol-17β, could not maintain replenishment of cytoplasmic receptor, the increase in RNA polymerase A activity or the secondary rise in RNA polymerase B activity. The basic anti-oestrogenic properties of tamoxifen may be implicit in its inability to maintain oestrogenic stimulation, and may be linked to its retention time within the nuclei.
EFFECT OF CHRONIC ADMINISTRATION OF GONADOTROPHIN RELEASING HORMONE AND THYROTROPHIN RELEASING HORMONE TO PUBERTAL BULLS ON PLASMA LUTEINIZING HORMONE, PROLACTIN AND TESTOSTERONE CONCENTRATIONS, THE NUMBER OF EPIDIDYMAL SPERM AND BODY WEIGHT
Authors: HAYNES N. B. , HAFS H. D. , MANNS J. G. 
Published: December 2008

SUMMARY
The experiment was designed to determine whether chronic administration of gonadotrophin releasing hormone (GnRH) plus thyrotrophin releasing hormone (TRH) to pubertal bulls would hasten sexual maturation. Nine bulls, three each at 4, 5 and 6 months of age were given i.m. injections of GnRH (0·4 μg/kg) plus TRH (2 μg/kg) three times daily (09.00, 16.00 and 23.00 h) for 30 days. Equivalent animals were given 0·9% saline vehicle as controls. At the outset of injections the 6-, 5- and 4-month-old bulls weighed 201, 157 and 169 kg respectively; equivalent weights at the final injection were 222, 186 and 198 kg. Plasma levels of LH, prolactin and testosterone were determined weekly around the injection given at 09.00 h. Twenty-four-hour plasma testosterone and LH profiles were obtained immediately after the last injection. The animals were unilaterally castrated at the end of this 24 h period and the second testis was removed 60 days later to assess testicular weights and epididymal sperm numbers. Surges of LH, testosterone and prolactin occurred throughout the experimental period in response to GnRH/TRH injection. The LH surge in response to the first injection was nearly fivefold larger than those measured at subsequent weekly intervals but prolactin and testosterone responses did not decline during the 28-day experimental period. Induced LH and prolactin peaks were larger than those occurring in the control bulls, but control animals produced an equivalent amount of testosterone. These bulls produced quasi-adult levels of testosterone even at 4 months of age. Chronic GnRH/TRH administration resulted in a depression of plasma testosterone, and a disruption of the normal episodic release pattern during the 24 h after the final treatment, but normal patterns returned within 60 days. Testicular weights and epididymal sperm numbers were not increased by chronic GnRH/TRH treatment.
TWO-SITE ASSAY OF BOVINE PARATHYROID HORMONE
Authors: WOODHEAD J. S. , DAVIES S. JOYCE , LISTER D. 
Published: December 2008

SUMMARY
A two-site assay has been developed for bovine PTH. This technique involves reaction of the antigen with two antibody molecules with the purpose of increasing specificity. In practice the hormone was extracted from plasma samples on to plastic tubes coated with antibody specific for PTH (1–34). Uptake was then measured using 125I-labelled antibodies specific for PTH (53–84). In this way a sensitive assay was obtained for PTH (1–84) which did not recognize molecular fragments. This technique was used in conjunction with immunoradiometric assays specific for either NH2-terminal (1–34) or CO2H-terminal (53–84) molecular fragments to study the clearance of infused PTH in the cow. Preliminary results support the hypothesis that the intact molecule is rapidly degraded in the peripheral circulation with the preferential disappearance of an NH 2-terminal fragment. Studies on endogenous secretion during calcium and EDTA infusions indicated that there was little intact hormone present at the times when CO2H-terminal immunoreactivity was readily measured.
RELATIONSHIPS AMONG BIOASSAY, RADIOIMMUNOASSAY AND DISC ELECTROPHORETIC ASSAY METHODS OF MEASURING RAT PROLACTIN IN PITUITARY TISSUE AND INCUBATION MEDIUM
Authors: ASAWAROENGCHAI HANSA , NICOLL C. S. 
Published: December 2008

SUMMARY
Relationships among bioassay, radioimmunoassay (RIA) and disc electrophoretic assay methods of estimating rat prolactin in pituitary tissue and incubation medium were determined. Highly significant correlations were obtained between disc electrophoretic and RIA estimates of prolactin in tissue and between bioassay and RIA estimates of prolactin in medium. Less significant relationships were obtained between disc electrophoresis and RIA (medium) and between bioassay and disc electrophoresis (tissue and medium). The relationship between bioassay and RIA of prolactin in the incubated tissue was not significant.
Regression analysis disclosed the following: the RIA measured slightly more, and the bioassay detected substantially more prolactin in tissue and medium than did disc electrophoresis; the bioassay detected about five times more prolactin in medium than did the RIA. No significant relationships were found within or among the assays for depletion and release of prolactin. The results indicate that secreted prolactin has increased bioassay activity relative to its detectability by disc electrophoresis and RIA.
OVULATION IN PRENATALLY ANDROGENIZED EWES
Authors: CLARKE I. J. , SCARAMUZZI R. J. , SHORT R. V. 
Published: December 2008

SUMMARY
The ovarian activity of prenatally androgenized ewes was studied by measuring plasma progesterone concentrations in daily samples of peripheral blood, and by examining the ovaries at laparotomy.
Ewes that were exposed to testosterone between days 30 and 80, 50 and 100 or 70 and 120 of foetal life by implanting their mothers with 1 g testosterone, failed to show regular overt oestrous cycles, although some of them ovulated, whereas ewes exposed to testosterone between days 90 and 140 of foetal life had normal oestrous cycles. The incidence of ovulatory failure appeared to increase with age in ewes treated between days 50 and 100 or days 70 and 120 of foetal life.
EFFECT OF OESTRADIOL-17β EXPOSURE ON THE SPONTANEOUS SECRETION OF GONADOTROPHINS IN CHRONICALLY GONADECTOMIZED RATS
Authors: HENDERSON S. R. , BAKER CHRISTINE , FINK G. 
Published: December 2008

SUMMARY
The effect of oestradiol-17β (administered in Silastic capsules) on gonadotrophin secretion in long-term gonadectomized rats has been investigated. In female rats, a daily afternoon surge of LH occurred which could be blocked by administering sodium pentobarbitone at 13.00 h. This, together with the fact that there was no significant difference between the LH-response to LH-releasing factor in the morning compared with the afternoon, supports the view that the LH surges are due to a neural rhythm. There was no significant diurnal variation in plasma FSH concentration, but an apparent diurnal variation was disclosed by administering sodium pentobarbitone on alternate days. There was no diurnal variation in plasma gonadotrophin concentrations in male animals implanted with an oestradiol capsule, or in animals of either sex bearing empty capsules.
BINDING OF HUMAN CHORIONIC GONADOTROPHIN TO RAT OVARY DURING DEVELOPMENT
Authors: SIEBERS J. W. , PETERS F. , ZENZES MARIA TERESA , SCHMIDTKE J. , ENGEL W. 
Published: December 2008

SUMMARY
Ovarian tissue of prenatal, newborn, and 5-day-old rats does not specifically bind 125Ilabelled HCG. Specific binding of HCG was first observed in ovaries of 10-day-old animals and binding increased with age. These results indicate that, contrary to rat testis, the HCG receptor in the rat ovary is not present during foetal and early postnatal development. Thus, the insensitivity of the ovary to endogenous and exogenous LH or HCG during this developmental period is due to the lack of specific receptors.
IMPAIRMENT OF THE CONTROL OF GONADOTROPHIN SECRETION AFTER OESTROGEN ADMINISTRATION TO ADULT FEMALE RATS
Authors: BROWN-GRANT K. , TER HAAR M. B. 
Published: December 2008

SUMMARY
The possible occurrence of long-term changes in gonadotrophin control mechanisms following the administration of oestrogen to adult female rats has been studied. Administration of 2·5 mg oestradiol benzoate (OB) to normal female rats at 60 days of age did not result in failure of ovulation at 120 days of age but significant impairment of the LH and FSH responses to progesterone after ovariectomy and oestrogen priming was observed at 160–180 days of age. Treatment with the same dose of OB at 60 days of rats injected with 10 μg testosterone propionate on Day 4 of postnatal life resulted in an increased incidence of failure of ovulation at 120 though not at 150 days of age but did not further impair the already reduced gonadotrophin response to progesterone at 160–180 days of age. Removal of the ovaries at 60 days of age did not modify the effects of oestrogen given at 60 days of age in either group nor did ovariectomy at 60 days improve the response of neonatally androgen-treated rats to progesterone at 160–180 days of age. The increases in plasma prolactin and TSH levels in response to oestrogen priming after ovariectomy were not affected in any of the experimental groups.
The administration of a long-acting oestrogen preparation (oestradiol cyclopentyl propionate, 2·5 mg at 60 days of age) to normal female rats suppressed ovulation and depressed plasma LH and FSH concentrations for at least 90 days; anterior pituitary weights were greatly increased and plasma prolactin concentrations were very high.
PROGESTAGEN EFFECTS ON ELICITATION OF AGGRESSIVE BEHAVIOUR IN MALE MICE
Authors: SOARES M. J. , KALBERER W. D. , ERPINO M. J. 
Published: December 2008

SUMMARY
Effects of progesterone on production of androgen-dependent aggression-eliciting pheromones were investigated. Two groups of anosmic (non-fighting) castrated mice treated with testosterone or with testosterone and progesterone, respectively, were attacked to the same degree by intact, isolated (fighting) mice while control mice (castrated only) were attacked less. The findings support the idea that progesterone may inhibit androgen-induced aggression via a neural and not via a somatic mechanism.
ANALYSIS OF ANDROGEN-BINDING PROTEIN IN MEDIA FROM SERTOLI CELL INCUBATIONS AND CYTOSOLS FROM RAT TESTES
Authors: ROMMERTS F. F. G. , KRÜGER-SEWNARAIN B. Ch. , GROOTEGOED J. A. , VAN DER MOLEN H. J. 
Published: December 2008

SUMMARY
Binding ability of androgen-binding protein (ABP) in concentrated media from Sertoli cell cultures and in various preparations of cytosols from rat testicular tissue have been estimated using dialysis and polyacrylamide gel electrophoresis (PAGE). Equilibrium dialysis in the presence of 1 nm-17β-hydroxy-5α-androstan-3-one appears to be the most convenient and reliable method for estimation of ABP if no other binding proteins are present. PAGE can be applied for estimation of ABP in samples which also contain other steroid-binding proteins. Estimated binding activities in culture media measured by PAGE and dialysis were essentially similar. Binding of androgens to ABP estimated with PAGE in cytosols prepared after sonication of testicular tissue was much lower than in cytosols obtained after homogenization using a Potter–Elvehjem homogenizer. When ABP was added to cytosols prepared after sonication or homogenization, approximately 50 and 90% respectively of the original binding of androgens to ABP was recovered.
EFFECT OF NEONATAL ANDROGENIZATION ON LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, PROLACTIN AND TESTOSTERONE LEVELS IN MALE RATS
Authors: MOGUILEVSKY J. A. , SCACCHI P. , RUBINSTEIN L. 
Published: December 2008

Department of Neuroendocrinology, Centro de Investigaciones Médicas Albert Einstein (CIMAE), Luis Viale 2831, Buenos Aires, Argentina and *Department of Obstetrics and Gynecology, UCLA School of Medicine, Los Angeles, California, U.S.A.
(Received 18 January 1977)
It is generally accepted that the administration of androgens to female rats in the neonatal period suppresses cyclic gonadotrophin release and a tonic gonadotrophin release occurs (Barraclough, 1966; Gorski, 1971). The tonic or male gonadotrophin pattern characteristically shows higher levels of plasma and pituitary follicle-stimulating hormone (FSH) and serum prolactin compared with female rats (Johnson, 1967, 1971; Kragt & Ganong, 1968; Neill, 1972).
In spite of the fact that the neonatal administration of androgens also induces changes in the reproductive physiology of adult male rats (Johnson & Witscht, 1963; Johnson, Yasuda & Sridharan, 1964; Morrison & Johnson, 1966), the effect of androgenization on gonadotrophin secretion in this sex is not clear.
The purpose of the present study
EFFECT OF THE HOST HORMONAL STATUS ON DEVELOPMENT OF SUCRASE AND ACID β-GALACTOSIDASE IN ISOGRAFTS OF RAT SMALL INTESTINE
Authors: KENDALL KEVIN , JUMAWAN JOCELYN , KOLDOVSKY OTAKAR , KRULICH LADISLAV 
Published: December 2008

Division of Biochemical Development and Molecular Diseases, Joseph Stokes, Jr Research Institute, Children's Hospital of Philadelphia and the Department of Pediatrics, Medical School of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A. and *Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas 75275, U.S.A.
(Received 6 January 1977)
It has been shown that diet and endocrine regulation are two factors influencing perinatal development of various intestinal enzymes (e.g. Koldovsky, 1972; Koldovsky, Jumawan & Palmieri, 1975; Yeh & Moog, 1975). So far, most studies have been performed in vivo; studies using organ cultures are hampered by the short viability of the preparations (Trier, 1976). Ferguson, Gerskowitch & Russell (1973) introduced an ingenious method of implanting under the kidney capsula of adult mice isografts of foetal small intestine, and these developed in a similar manner to normal intestine in situ. Since the isografts were never exposed to external stimuli (food, etc.),
CAPILLARY BLOOD FLOW IN THE GENITAL TRACTS OF CONSCIOUS EWES: CYCLIC CHANGES AND THE EFFECT OF OVARIAN HORMONES
Authors: BROWN B. W. , MATTNER P. E. 
Published: December 2008

The indicator fractionation technique with [86Rb]rubidium chloride as the indicator was used in conscious animals to determine the relative blood flow (RBF) as a measure of capillary blood flow in regions of the genital tract of cyclic ewes and of hormonally treated ovariectomized ewes. The RBF values in the ampulla, isthmus, uterus and cervix of cyclic ewes were markedly raised at pro-oestrus and declined thereafter to low levels during the remainder of the oestrous cycle. On Day 4 a small secondary rise in flow occurred in the ampulla and isthmus.
In ovariectomized ewes, oestradiol induced high levels of RBF in the ampulla, isthmus, uterus and cervix whether the animals had been treated previously with progesterone or given concurrent small doses of progesterone. Though progesterone given alone caused a significant rise in RBF in the uterus, this effect appeared to be one occurring only during active re-growth of regressed tracts.
The findings are discussed in relation to oestradiol inducing a stimulatory effect on RBF in the genital tract of the ewe around oestrus but not at Days 3–4 of the oestrous cycle.
PHOTOPERIODIC CONTROL OF GONADOTROPHIN SECRETION IN THE RAM: A DETAILED STUDY OF THE TEMPORAL CHANGES IN PLASMA LEVELS OF FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE AND TESTOSTERONE FOLLOWING AN ABRUPT SWITCH FROM LONG TO SHORT DAYS
Authors: LINCOLN G. A. , PEET M. J. 
Published: December 2008

SUMMARY
Six adult Soay rams were housed under artificial lighting conditions of long days (16 h light: 8 h darkness) for 4 months and this caused the animals to lapse into a state of reproductive quiescence with low levels of gonadotrophins in the circulation and regressed testes secreting very low amounts of testosterone. The photoperiod was changed abruptly to short days (8 h light: 16 h darkness) to induce a resurgence of sexual activity, and a detailed study was made of the pituitary and testicular responses over the first 100 days.
Plasma levels of LH and FSH first began to increase between days 6 and 12 of short days, and rose progressively until days 33–54 before declining again. Testicular growth of the rams began on days 19–26 and continued for most of the remaining period of study. Plasma testosterone levels rose in parallel with the growth of the testes, and were greatly increased by day 100 when gonadotrophin levels were reduced.
At most stages there were short-term fluctuations in the plasma levels of FSH, LH and testosterone indicative of episodic secretion. Peaks in plasma levels of LH were especially conspicuous and from the changes in frequency and amplitude of these peaks it was possible to predict the way in which photoperiod influenced gonadotrophin secretion by its effect on hypothalamic LH-RH secretion. A slight 24 h rhythm in the plasma levels of all three hormones was observed, and the significance of this in relation to the photoperiodic response is discussed.
INHIBITION OF THYROTROPHIN-RELEASING HORMONE RESPONSIVENESS BY PHYSIOLOGICAL CONCENTRATIONS OF THYROID HORMONES IN THE CULTURED RAT PITUITARY GLAND
Authors: LEWIS M. , YEO P. P. B. , GREEN E. , EVERED D. C. 
Published: December 2008

SUMMARY
Diced quarter anterior pituitaries from mature female Wistar rats were cultured in synthetic medium with or without added serum. Using each culture as its own control, the thyrotrophin-releasing hormone (TRH) dose–thyrotrophin (TSH) response characteristics of both media were similar; significant TSH secretion being stimulated at TRH doses around 1·5 × 10−9 mol/l. During days 1–3 of culture, basal TSH secretion fell significantly but TRH responsiveness was unchanged. Neither tri-iodothyronine (T3) nor thyroxine (T4) influenced basal TSH secretion.
In both culture media inhibition of TRH responsiveness was demonstrated with concentrations of T3 and T4 within the ranges 1·5 × 10−12 to 1·5 × 10−9 mol/l for T3 and 6·5 × 10−10 to 6·5 × 10−7 mol/l for T4. Equivalent inhibition was accompanied by similar T3 concentrations whether T3 or T4 supplements were used, suggesting that T4 itself has no feedback action. The similar concentrations of T3 required to inhibit TRH responsiveness in media either with or without serum suggest that the pituitary is responsive not only to free but also to total thyroid hormone concentrations, since serum-free medium contains no thyroid hormone-binding protein.
EFFECT OF DIBUTYRYL CYCLIC AMP AND OESTRADIOL ON INCORPORATION OF [3H]LEUCINE INTO THE PROTEINS OF LUMINAL FLUID OF THE RAT UTERUS
Authors: SURANI M. A. H. , WEBB F. T. G. 
Published: December 2008

SUMMARY
An injection of 12·5 nmol dibutyryl cyclic AMP (dbcAMP) into each uterine horn of ovariectomized rats maintained on progesterone alone, enhanced incorporation of [3H]leucine into uterine luminal proteins. A value of 11·73 × 103 c.p.m. [3H]leucine incorporated/ rat was found after injection of dbcAMP compared with 3·69 × 103 c.p.m./rat after injection of saline. An injection of 1·0 μg oestradiol, in contrast, gave 58·05 × 103 c.p.m./rat. Electrophoretic analysis showed that the radioactively labelled proteins found after an injection of dbcAMP or oestradiol were qualitatively similar to those detected on day 5 of pregnancy, the day of blastocyst implantation. The nucleotide thus apparently elicits a uterine response similar to that observed after an injection of oestradiol.
PHYSIOLOGICAL ACTIONS OF HUMAN FOLLICLE-STIMULATING HORMONE AND ITS β-SUBUNIT IN REPTILES
Authors: LICHT PAUL , GALLO ANTONELLA BONA , HARTREE ANNE STOCKELL , SHOWNKEEN RATNA C. 
Published: December 2008

SUMMARY
The actions of human follicle-stimulating hormone (hFSH) and its β-subunit were examined in several assays in reptiles, including effects on lizard testicular activity (growth and androgen production) in vivo, and stimulation of androgen production by snake testes and competition for binding of 125I-labelled hFSH in lizards and snakes in vitro. Binding was also examined with mammalian tissues.
The hFSH was highly steroidogenic in the snake and lizard; otherwise results were similar to those observed in mammals. In all cases, the potency of the β-subunit was only a few per cent of the intact hormone. The potency of hFSH in vivo compared with NIH-FSH ovine standards was several 100 times greater than in vitro. Results for stimulation of androgen production in vivo closely paralleled those for binding assays in both reptiles and mammals. In contrast to previous results for ovine FSH β-subunit, human FSH β-subunit has little if any FSH biological activity in reptiles.
VARIATIONS IN STORED AND PLASMA CONCENTRATIONS OF ANDROGENS AND LUTEINIZING HORMONE DURING SEXUAL DEVELOPMENT IN THE COCKEREL
Authors: SHARP P. J. , CULBERT J. , WELLS J. W. 
Published: December 2008

SUMMARY
The concentrations of luteinizing hormone (LH) and testosterone in the plasma and the stored levels of LH, testosterone and androstenedione were measured in cockerels aged 8–29 weeks. The onset of puberty occurred between 16 and 24 weeks of age, when the testes entered a phase of rapid growth and spermatogenesis was completed. The following sequence of endocrine events was found to be associated with the onset of puberty: a fall in the amount of androstenedione in the testes before any evidence of increased testicular growth; an increase in the total amount of LH in the pituitary gland as the testes started to enlarge; an increase in the total amount of testosterone in the testes and in the concentration of LH in the plasma; an increase in the concentration of testosterone in the plasma. An increase in the rate of growth of the comb and testes preceded a detectable increase in the levels of LH and testosterone in the plasma. The increase in the amount of testosterone in the plasma which occurred after the initial increase in the concentration of LH was associated with the final stages of spermatogenesis, a decrease in the rate of body growth and a temporary reduction in the amount of LH secreted.
EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON ADENYLATE CYCLASE ACTIVITY AND TESTOSTERONE CONTENT IN RAT TESTICULAR MITOCHONDRIA
Authors: SULIMOVICI SOREL , ROGINSKY M. S. 
Published: December 2008

The adenylate cyclase activity and the concentration of testosterone in testicular mitochondria from immature rats were measured after administration of human chorionic gonadotrophin (HCG) or dibutyryl cyclic AMP in vivo or in vitro. Intratesticular injection of HCG produced an increase in adenylate cyclase activity which preceded the rise in the level of testosterone, whereas addition of the trophic hormone in vitro resulted in simultaneous increases. Administration of dibutyryl cyclic AMP in vivo enhanced the testosterone content of the mitochondria. However, the cyclic nucleotide added in vitro at concentrations up to 5 mmol/l had no effect. Cycloheximide injected intraperitoneally before the administration of HCG abolished the stimulatory effect of the trophic hormone on the level of testosterone in the mitochondria, whereas chloramphenicol had no effect.
These results, although they confirm the role of cyclic AMP as an intermediate in the stimulatory effect of HCG on the concentration of testosterone in rat testis, do not support a role for mitochondrial adenylate cyclase in this action. A protein regulator(s) formed extramitochondrially appears to be involved in the stimulatory effect of gonadotrophins on steroidogenesis.