bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHANGES IN CONCENTRATIONS OF FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE, PROLACTIN AND PROGESTERONE IN THE PLASMA OF EWES DURING THE TRANSITION FROM ANOESTRUS TO BREEDING ACTIVITY
Authors: WALTON J. S. , McNEILLY JUDITH R. , McNEILLY A. S. , CUNNINGHAM F. J. 
Published: December 2008

The plasma concentrations of FSH, LH, prolactin and progesterone were measured throughout anoestrus and during the resumption of cyclic activity in two groups of ewes. Group A was maintained under conditions of natural daylength throughout the experiment, whereas Group B was exposed to 6 h of light and 18 h of darkness, the change being made abruptly on the longest day. In those ewes kept on short days, oestrus and ovulation occurred 18·3 days (P < 0·05) and 23·4 days (P < 0·001) earlier than in the ewes under conditions of natural daylength. Ovulation preceded oestrus by 18·6 days and 23·1 days in Groups A and B respectively.
The occurrence of ovulation was detected by the determination of plasma progesterone concentrations. In all ewes, progesterone levels were basal until the first ovulation when the pattern of secretion was typical of that seen during the oestrous cycle. In the 4 days before ovulation, the plasma progesterone concentration increased slowly to reach a maximum of 0·66 ± 0·12 (s.e.m.) ng/ml on day − 1. The first ovulation was associated with a substantial surge of LH. Similar release of LH, thought to be related to the increased progesterone secretion, was also observed on day −5. Sporadic release of LH was also found before this time in some animals.
Plasma concentrations of FSH fluctuated randomly throughout anoestrus and during the transition to established oestrous cycles. These changes were not apparently related to ovulation. Throughout anoestrus, prolactin concentrations were raised but always declined before the time of ovulation. The fall in prolactin concentrations occurred sooner in the ewes on short days, pointing to a relationship with the decreased daylength.
These data suggest that the return to oestrous cycles may be brought about by the removal of an antigonadotrophic effect exerted by high concentrations of prolactin in the blood during anoestrus.
METABOLISM OF ANDROGENS IN VITRO BY THE SUBMAXILLARY SALIVARY GLAND OF THE MATURE DOMESTIC BOAR
Authors: BOOTH W. D. 
Published: December 2008

Homogenates of the submaxillary glands of mature domestic boars were incubated with radioactively labelled C19 steroids. The metabolism of [7α-3H]dehydroepiandrosterone and [7α-3H]androstenedione was primarily to the end products 5α-androstane-3,17-dione and androsterone, but some testosterone, 5α-dihydrotestosterone and 5α-androstane-3α,17β-diol were also formed. When [7α-3H]5-androstene-3β,17β-diol was used as a substrate, the major metabolite was testosterone. Both [7α-3H]5-androstene-3β,17β-diol and [1α,2α-3H]-testosterone were converted to 5α-dihydrotestosterone and high yields of 5α-androstane-3α,17β-diol, but only small yields of 5α-androstane-3β,17β-diol and androsterone were obtained. High yields of 5α-androstane-3α,17β-diol and to a lesser extent 5α-androstane-3β,17β-diol were formed from the substrate [1α,2α-3H]5α-dihydrotestosterone. Conversely, when both 3H-labelled androstanediols were used as substrates, 5α-dihydrotestosterone was formed in equal amounts together with a large yield of 5α-androstane-3α,17β-diol from the 3β-epimer. There was no evidence for steroid sulphatase or aromatase activity in these incubations. These findings support the prohormone concept that precursor steroids of testosterone, known to be present in boar testis, could act as an additional source of potent androgens in peripheral target organs to androgens in this species.
In a number of incubations with [1α,2α-3H]testosterone, free oestradiol-17β and oestrone, but not oestrone sulphate enhanced the formation of androstenedione, but reduced the formation of 5α-dihydrotestosterone. However, both free and conjugated oestrogen reduced the formation of 5α-androstane-3α,17β-diol. These findings are discussed in relation to the high levels of oestrogen found in male pigs.
SELECTIVE RELEASE OF FOLLICLE-STIMULATING HORMONE DURING THE PERIOD OF OVULATION INDUCED BY HUMAN CHORIONIC GONADOTROPHIN IN DIOESTROUS RATS
Authors: SASAMOTO SHUJI , HARADA SHIGEO , TAYA KAZUYOSHI 
Published: December 2008

Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan
(Received 2 May 1977)
When an amount of human chorionic gonadotrophin (HCG) sufficient to cause ovulation is given to 4-day cyclic rats on the day of dioestrus, premature ovulation is induced the next morning (Eto & Imamichi, 1955). The pattern of release of follicle-stimulating hormone (FSH) responsible for the initiation of follicular maturation of the next set of follicles (Schwartz, 1969; Welschen & Dullaart, 1976) after HCG-induced ovulation has not been previously evaluated. The present communication is concerned with this problem and indicates that a large amount of FSH is released within 12 h of administration of HCG, with only a small concomitant rise in the concentration of luteinizing hormone (LH).
Adult female Wistar rats were maintained under a 14 h light : 10 h darkness schedule (lights on 05.00 h), and those showing three or
INTRAOCULAR OVARIAN ISOGRAFTS IN MALE MICE AND THEIR RESPONSE TO HUMAN PLACENTAL LACTOGEN
Authors: TALAMANTES F. , GUZMAN R. , LOPEZ J. 
Published: December 2008

Division of Natural Sciences and Oakes College, Thimann Laboratories, University of California, Santa Cruz, California 95064, U.S.A.
(Received 6 May 1977)
The luteotrophic activity of human placental lactogen (HPL) in non-primates was demonstrated by its ability to maintain the induced decidual reaction in hypophysectomized pseudopregnant rats (Josimovich, Atwood & Goss, 1963). In the mouse, HPL has been reported to induce hyperaemia of corpora lutea of ovulation in non-parous mice (Kavocic, 1968). However, because of the design of the study, it was not possible to determine the duration of hyperaemia in those HPL-induced corpora lutea.
Ovarian isografts in male mice develop mature follicles that only rarely luteinize spontaneously. Such follicles luteinize upon the administration of luteinizing hormone (LH) and the resultant corpora lutea only show hyperaemia of function if a luteotrophic hormone is then given (Browning, 1968). The present investigation was undertaken to examine the hyperaemic response of ovarian isografts in
CHANGES IN CATECHOLAMINE CONTENT OF THE MEDIAN EMINENCE PRECEDE THE PRO-OESTROUS SURGES OF LUTEINIZING HORMONE AND PROLACTIN
Authors: NEGRO-VILAR A. , CHIOCCHIO SARA R. , TRAMEZZANI J. H. 
Published: December 2008

Instituto de Neurobiologia, Serrano 665, Buenos Aires, Argentina
(Received 9 June 1977)
Changes in the levels of catecholamines in the hypothalamus during the oestrous cycle have been reported by Donoso, Stefano & Biscardi (1966) and Stefano & Donoso (1967). Shaar & Clements (1974) found that lower concentrations of dopamine and noradrenaline than those found in the hypothalamus can inhibit the release of prolactin from the rat pituitary gland. We have studied the levels of noradrenaline and dopamine in the median eminence around the time of the spontaneous preovulatory release of hormones.
Adult female Holtzman rats showing at least three consecutive 4 day cycles, were killed by decapitation at 09.30, 13.00 and 17.30 h on the days of dioestrus I and pro-oestrus. After decapitation, blood was collected into centrifuge tubes and the brains were immediately removed and frozen on solid CO2. Serum was separated by centrifugation and stored at −20 °C
FAILURE OF NEUROHYPOPHYSIAL NEUROSECRETORY GRANULE LYSATE TO LIBERATE ARGININE-VASOPRESSIN FROM SYNTHETIC MODEL PROHORMONES SIMULATING COVALENT ATTACHMENT OF ARGININE-VASOPRESSIN TO NEUROPHYSIN
Authors: MOORE G. J. , SWANN R. W. , LEDERIS KARL 
Published: December 2008

Division of Pharmacology and Therapeutics, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
(Received 13 June 1977)
Several lines of circumstantial evidence suggest that the neurohypophysial hormones may be biosynthesized in the form of larger peptides (prohormones) which are degraded to the free hormones during passage of the neurosecretory granules from the hypothalamus to the neurohypophysis (Vogt, 1953; Sachs & Takabatake, 1964; Pickering, Jones & Burford, 1971). Furthermore, it has been suggested that the hormone carrier proteins, the neurophysins, may at some stage in the biosynthesis, form part of the putative prohormones (Hope & Pickup, 1974).
In cattle, arginine-vasopressin (AVP) is associated with bovine neurophysin II (Dean, Hope & Kazič, 1968), the complete amino acid sequence of which has been elucidated by Schlesinger, Capra & Walter (1974) and Wuu & Crumm (1976). In the present study, two dodecapeptide analogues of AVP in which the peptide chain was elongated
EFFECTS OF TESTOSTERONE ON HEPATIC LIPID METABOLISM IN THE MATURE FEMALE DOMESTIC FOWL
Authors: PEARCE J. 
Published: December 2008

Department of Agricultural and Food Chemistry, The Queen's University of Belfast, Newforge Lane, Belfast, BT9 5PX, and Department of Agriculture, Northern Ireland
(Received 1 July 1977)
Before the onset of egg laying in the domestic fowl, there are increases in the lipid content of the plasma and liver (Chaikoff, Lorenz & Entenman, 1941; Heald & Badman, 1963). These changes are the result of oestrogen secretion by the ovary (Sturkie, 1965). Hepatic lipogenic enzymes also increase in activity during the onset of sexual maturity and their specific activities are greater in the laying hen than in the mature cockerel (Pearce, 1971); similar changes in the activities of hepatic lipogenic enzymes have been observed in oestrogen-treated immature pullets (Balnave & Pearce, 1974). The synthesis of yolk proteins in the liver is also induced by the administration of oestrogen to immature pullets and cockerels (Gruber, 1972). The action of oestrogen is antagonized by
METABOLISM OF TESTOSTERONE IN THE ANTERIOR PITUITARY GLAND AND THE CENTRAL NERVOUS SYSTEM OF THE EUROPEAN STARLING (STURNUS VULGARIS)
Authors: MASSA R. , CRESTI L. , MARTINI L. 
Published: December 2008

The metabolism of testosterone was studied in vitro in anterior pituitary, hypothalamic and hyperstriatal tissues taken from male European starlings in the autumn. In all the tissues studied, testosterone was converted into 5α-androstan-17β-ol-3-one (5α-DHT), 5β-androstan-17β-ol-3-one (5β-DHT), 5β-androstane-3α,17β-diol (5β-THT), 5β-androstane-3,-17-dione and androst-4-ene-3,17-dione.
The 5α-DHT was produced in significantly greater amounts by the pituitary gland than by the hypothalamus and hyperstriatum. The amount of 5α-DHT produced, however, was very low in comparison with the amounts of 5β-reduced metabolites. The amount of 5β-reductase was also higher in the pituitary gland than in the two nervous tissues. The ratios between the production of 5β-DHT, 5β-THT and 5β-androstane-3,17-dione were, however, different in the three tissues: 5β-DHT was produced in the greatest quantities by the hyperstriatum, while the production of 5β-THT, 5β-androstane-3,17-dione and androst-4-ene-3,17-dione was greatest in pituitary tissue.
The role of 5α- and 5β-reduced metabolites in the pituitary gland and in the brain of birds is unknown, but some possibilities arising from the present results are discussed.
FORMATION OF STEROID HORMONES IN VITRO BY DEVELOPING CORPORA LUTEA OF THE RABBIT
Authors: SUZUKI AKIRA , MORI TAKAHIDE , NISHIMURA TOSHIO 
Published: December 2008

Rabbits were injected with human chorionic gonadotrophin (HCG), and slices of developing corpora lutea taken from the ovaries 15, 18, 24, 48, 72 and 96 h after injection were incubated with [1-14C]sodium acetate at 37 °C for 3 h. The incorporation of labelled acetate into ten steroids, including progestagens, androgens and oestrogens, was analysed.
In the initial step of corpus luteal formation, the specific incorporation (incorporation of [1-14C]acetate/100 mg tissue) increased sharply. The major steroidal products were progesterone, 17-hydroxyprogesterone and 20α-hydroxypregn-4-en-3-one. Between 18 and 48 h, the increase in specific incorporation was more gradual than in the initial step. Although the pattern was also dominated by progestagens, a temporary increase in the incorporation of acetate into androgens and oestrogens was observed. In the final step, a sharp rise in the total incorporation (incorporation of [1-14C]acetate/corpus luteum) was found, whereas the specific incorporation increased only slightly. The principal steroids produced were progesterone, pregnenolone and 20α-hydroxypregn-4-en-3-one. Incorporation into C19 steroids declined markedly and that into C18 steroids could not be detected. This profile of steroidogenesis 96 h after injection of HCG was similar to that of the corpus luteum in pregnancy.
Thus marked quantitative and qualitative changes have been demonstrated during the period of formation of corpora lutea in the rabbit.
PLASMA CALCITONIN LEVELS IN PREGNANT AND NEWBORN RATS
Authors: GAREL JEAN-MICHEL , JULLIENNE ANNICK 
Published: December 2008

A radioimmunoassay for rat calcitonin was developed, which used a heterologous system that involved labelled human calcitonin, an antibody developed against purified human calcitonin and purified or synthetic rat calcitonin as a standard. The sensitivity of the assay was 0·3 ng rat calcitonin/ml plasma. The levels of calcitonin in the plasma of pregnant rats were studied in the last week of gestation and compared with the levels found in the plasma of control virgin female rats. The level of calcitonin in the plasma after 17·5 days of gestation was already higher than that in the control rats, it increased further up to 19·5 days and decreased at 21·5 days. Infusion of calcium into pregnant rats for 1 h after 21·5 days of gestation induced a sixfold increase in the level of calcitonin in the plasma after 30 min, and a threefold increase after 1 h.
The level of calcitonin in the plasma of fed and unfed newborn rats was measured 2, 6, 12 and 16 h after birth. At each stage, the concentration of calcitonin was higher in fed than in unfed animals. Stomach gavage of fat (triglycerides) in fasted rats born 2 h earlier stimulated secretion of calcitonin; administration of pentagastrin or glucagon had no effect on the level of calcitonin in the plasma. Subcutaneous injection of a calcium load to fasted newborn rats (2 hours old) increased the level of calcitonin in the plasma after 30 min.
These results demonstrate that during gestation calcitonin has a comparable role in rats to that already found in ruminants. They also substantiate the part played by the fat present in milk as a stimulus (through some unknown gastrointestinal hormones) for secretion of calcitonin during suckling, and the involvement of calcitonin secretion in the regulation of nutrient absorption in the newborn rat.
PROGESTERONE METABOLISM IN THE FEMALE GORILLA
Authors: YOUNGLAI E. V. , COLLINS D. C. , GRAHAM C. E. 
Published: December 2008

Department of Obstetrics and Gynecology, McMaster University Medical Centre, Hamilton, Ontario, Canada, L8S 4J9, *Department of Medicine, Emory School of Medicine, Atlanta, Georgia 30303, U.S.A. and †Yerkes Regional Primate Center, Atlanta, Georgia 30322, U.S.A.
(Received 26 April 1977)
It is becoming evident that rodents and rhesus monkeys are not suitable models for the study of all aspects of human reproductive endocrinology (Hobson, Coulston, Faiman, Winter & Reyes, 1976). Apes, on the other hand, closely resemble man in many aspects of their endocrinology (Graham, 1976). As part of a continuing study on progesterone metabolism among the great apes, we have found that the single most abundant urinary metabolite of progesterone is 5β-pregnane-3α,20α-diol (pregnanediol) in the adult female chimpanzee (YoungLai, Graham & Collins, 1975) and is similar to that in the immature chimpanzee (Romanoff, Grace, Sugarman & Pincus, 1963). This is in contrast to the macaques where androsterone is the major metabolite
PATHWAYS FOR THE BIOSYNTHESIS OF OESTRADIOL IN THE RABBIT OVARIAN FOLLICLE IN VITRO
Authors: PATWARDHAN V. V. , LANTHIER A. 
Published: December 2008

Laboratoire d'Endocrinologie, Hópital-Notre-Dame et Département de Médecine, Université de Montréal, Montréal, Canada
(Received 8 June 1977)
In ovarian tissues, the synthesis of oestrogen from pregnenolone can proceed via progesterone and the 3-oxo-4-unsaturated steroid pathway or by way of dehydroisoandrosterone and the 5-unsaturated steroid pathway. In human ovaries, the follicle seems to prefer the 5-unsaturated pathway for formation of oestrogen (Ryan & Petro, 1966), whereas in the corpus luteum, the 4-unsaturated steroid pathway may be the only one that is operative (Ryan, 1963). The situation is not so clear in other species. In the rabbit, a reflex ovulator, ovarian follicles are known to secrete oestradiol (YoungLai, 1972). Furthermore, isolated follicles can form oestradiol, androgens and progesterone from endogenous (Mills, 1975) or exogenous (Mills & Savard, 1972) precursors in vitro. Mills & Savard (1972) incubated rabbit follicles with [1-14C]acetate and isolated labelled oestradiol and intermediates involved in the 4- and 5-unsaturated steroid
LEVELS OF TESTOSTERONE AND LUTEINIZING HORMONE IN THE PLASMA OF YOUNG POST-PUBERTAL BULLS AFTER INJECTION OF HUMAN CHORIONIC GONADOTROPHIN OR DEXAMETHASONE AND HUMAN CHORIONIC GONADOTROPHIN
Authors: THIBIER M. , ROLLAND O. 
Published: December 2008

Institut National Agronomique Paris-Grignon, Centre de Grignon, Franceand *Laboratoire d'Hormonologie, U.N.C.E.L.A., 13 Rue Jouet, 94700 Maisons-Alfort, France
(Received 21 July 1977)
There is now very good evidence that in young or adult bulls, as in many species, the secretion of luteinizing hormone (LH) and testosterone is episodic (Katongole, Naftolin & Short, 1971; Thibier, 1975, 1976). Each individual discharge of LH can result in transient stimulation of the testes and hence in an associated increase in the level of testosterone. It has recently been shown that administration of dexamethasone dramatically reduces the level of testosterone in the plasma, with no fluctuations during the next 30h; simultaneously, the level of LH also tends to decrease (Thibier & Rolland, 1976). We have now examined the levels of testosterone and LH in the peripheral plasma of young post-pubertal bulls after treatment with human chorionic gonadotrophin (HCG) alone, or HCG and dexamethasone. Twelve French Friesian
CHARACTERIZATION AND ASSAY OF THE PROGESTERONE RECEPTOR IN RAT UTERINE NUCLEI
Authors: VU HAI M. T. , MILGROM E. 
Published: December 2008

SUMMARY
Rat uterine nuclei containing unlabelled progesterone–receptor complexes were incubated at 0 °C with the synthetic progestogen [3H]R5020 (17,21-dimethyl-19-norpregna-4,9-diene-3,20-dione). Complete exchange of steroid bound to the receptor was observed after 5–6 h. For longer times (up to 26 h) there was no further change in the concentration of steroid–receptor complexes, but the non-specific binding was increased. Saturation of nuclear receptors was obtained with a concentration of 5–10 nm-[3H]R5020. Competition with unlabelled steroids showed that only progestogens inhibited the binding of [3H]R5020 to nuclei. Optimum experimental conditions to reduce the non-specific binding to nuclei were established, and a method for the assay of nuclear progesterone–receptor complexes was devised, based on these characteristics. The concentration of nuclear receptors was low in oestradiol-primed ovariectomized rats; adrenalectomy gave rise to slightly lower values. Injection of the rats with progesterone resulted in a 5·5-fold increase in the number of nuclear receptors and a parallel decrease in the number of cytosol receptors. Similar injections of corticosterone and testosterone were without effect. Nuclear receptors were also shown to be stable in uteri kept in liquid nitrogen for up to 3 weeks. This assay may be used to study the correlation of a biological response to progesterone with the extent of receptor occupation in the nuclei.
EFFECTS OF OVARIECTOMY, PROGESTERONE AND OESTROGEN ON UTERINE CATECHOLAMINE CONCENTRATIONS IN RELATION TO PARTURITION IN RATS
Authors: MALTIER J. P. , CAVAILLÉ F. 
Published: December 2008

SUMMARY
In control rats, the concentrations of catecholamines in the uterus were markedly modified between days 21 and 22 of gestation, just before parturition; there was a considerable decrease in the concentration of adrenaline (−73%), whereas the level of noradrenaline increased significantly.
Of rats ovariectomized on day 19, 59% underwent abnormal parturition, and the uterine concentration of catecholamines remained constant; on day 22 of gestation, the concentration of adrenaline was twice as high as that in control rats. Injections of progesterone during late pregnancy resulted in prolonged pregnancies in 100% of those rats injected. Changes in the uterine concentrations of catecholamines observed in control rats did not take place in the injected animals, and on day 22 of gestation the concentration of adrenaline was three times that in control rats. Injections of oestrogen in late pregnancy advanced littering in rats which normally produced late litters. In the uterus, a considerable decrease in the concentration of adrenaline was observed and this was similar to that observed in control rats, except that the reduction occurred earlier.
Sham treatments (sham ovariectomies or injections of solvent in which oestrogen or progesterone were administered) had no effect on the timing of parturition or the uterine concentration of catecholamines, compared with control rats.
The concentration of adrenaline in the uteri of pregnant rats was controlled by steroid hormones and it seems that a very low concentration was required for normal parturition.
HYPOTHALAMIC PARAVENTRICULAR UNIT ACTIVITY DURING LABOUR IN THE RAT
Authors: BOER K. , NOLTEN J. W. L. 
Published: December 2008

SUMMARY
The spike activity of 191 antidromically identified paraventricular units was recorded during labour and the oestrous cycle of rats under urethane anaesthesia. Accelerated bursts of neuronal activity, as reported to occur during suckling, were not observed and changes in firing rate were not correlated with individual uterine contractions. There was, however, an increase in the magnitude of the mean spontaneous firing rate of antidromically identified neurosecretory cells during labour, as compared with all stages of the oestrous cycle. This increase was mainly caused by (1) a marked reduction (>25%) in the percentage of totally silent cells and (2) an increase in the magnitude of the mean firing rate of the phasically firing units (1·58–3·44 spikes/s).
It was concluded from these increases in spike activity that the tonic release of neurohypophysial hormones is stimulated during labour, and that this may contribute to the induction and course of labour.