bluuebunny/crossref_metadata_2025_split huggingface dataset:
REVERSAL OF BETAMETHASONE-INDUCED INHIBITION OF INTESTINAL CALCIUM ABSORPTION BY 1α-HYDROXYCHOLECALCIFEROL
Authors: FOX J. , CARE A. D. , MARSHALL D. H. 
Published: December 2008

SUMMARY
The intestinal absorption of calcium has been studied in conscious, unstressed pigs, using a modification of the double isotope technique. The oral administration of betamethasone (1 mg/day) to four pigs (25–33 kg) for 4 weeks reduced the calcium absorption coefficient, calculated after the intravenous and oral administration of 47Ca2+, by a mean value of 66%. The oral administration of 1α-hydroxycholecalciferol (2 μg/day) in combination with betamethasone (1 mg/day) for a further 4 weeks returned the absorption coefficient to the control value.
ACTION OF PROSTAGLANDIN E2 ON THE RELEASE OF CATECHOLAMINES FROM THE CANINE ADRENAL GLAND AND ITS INTERACTION WITH ACETYLCHOLINE
Authors: YAMASHITA K. , MIENO M. , SHIMIZU T. , YAMASHITA ER. 
Published: December 2008

SUMMARY
The effect of prostaglandin E2 (PGE2) on the secretion of adrenaline and noradrenaline by the adrenal gland and the interaction between PGE2 and acetylcholine in the adrenal medulla were examined in anaesthetized dogs. In splanchnicotomized dogs, i.v. injection of PGE2 failed to induce any secretion of catecholamines from the adrenal gland, whereas administration of PGE2 into the lumboadrenal artery resulted in a slight, approximately dose-dependent increase in catecholamine secretion within 2 min of the injection. This effect of PGE2 was unaffected by i.v. administration of atropine. Intravenous administration of acetylcholine 1 min after the administration of PGE2 into the lumboadrenal artery of splanchnicotomized atropine-treated dogs had a markedly greater effect on adrenal catecholamine secretion; the resultant output was about twice that evoked by acetylcholine in the absence of PGE2. The effect was more than additive, since the response to acetylcholine was at least one order of magnitude greater than that to PGE2. This indicates that PGE2 and acetylcholine may act synergistically in the adrenal medulla.
BIOCHEMICAL CHANGES IN THE CORPORA LUTEA OF PREGNANT AND LACTATING HAMSTERS
Authors: CHATTERJEE SUDHA , GREENWALD G. S. 
Published: December 2008

SUMMARY
Progesterone was secreted by hamster corpora lutea between days 1 and 15 of pregnancy; on day 14, the concentration in the peripheral plasma reached a maximum. A pronounced fall in luteal weight began on the day after parturition and the corpora lutea had virtually disappeared by days 4–5 post partum. The concentration of protein and the weights of the corpora lutea reached peak levels on days 12 and 14 respectively. The highest levels of luteal RNA were reached on days 12–13. The concentration of DNA in the corpora lutea was constant throughout pregnancy, indicating that hypertrophy rather than hyperplasia accounted for the increase in luteal weight.
Luteal concentrations of cholesterol and its esters were unchanged between days 1 and 14 of pregnancy except for a significant decline in the level of cholesteryl ester on days 8 and 13. During the final stages of regression of the corpora lutea during lactation, the luteal concentrations of free and esterified cholesterol rose to three and ten times respectively, the values obtained on day 2 of pregnancy. A significant increase in the concentration of acid and alkaline phosphatase began on day 16 of pregnancy correlated with the onset of structural luteolysis.
The activity of luteal glucose-6-phosphate dehydrogenase peaked on days 2 (comparable to the value on day 2 of the oestrous cycle) and 13 of pregnancy and day 3 of lactation. The high levels on these days may be associated either with luteal steroidogenesis during pregnancy or with lipid metabolism during the post-partum involutional phase. The activity of luteal 3β-hydroxysteroid dehydrogenase was relatively constant except for significant decreases on days 10 and 13 of pregnancy.
The results indicate that the activities of all of the biochemical variables in the corpora lutea of pregnancy were highest between days 11 and 13.
STEROID FEEDBACK ON LUTEINIZING HORMONE SECRETION DURING SEXUAL MATURATION IN THE PIG
Authors: ELSAESSER F. , PARVIZI N. , ELLENDORFF F. 
Published: December 2008

The effects of gonadal secretions on the release of LH and the stimulation of LH secretion by oestradiol have been investigated in newborn male and female miniature pigs; the differences in the feedback action of testosterone in newborn and pubertal male pigs were also studied.
Hemi-orchidectomy or orchidectomy of 1-week-old pigs had no effect on the level of LH in the plasma; total orchidectomy significantly reduced the levels of testosterone (P<0·01) and progesterone (P<0·05). In female pigs ovariectomized at 1 week of age, the concentration of LH in the plasma decreased, with a strong negative correlation between the level of LH and age (r = −0·41; P < 0·05). The plasma concentration of progesterone was generally low and unaffected by ovariectomy. Orchidectomy and treatment of male pigs, at 1 week of age, with testosterone (6 mg/kg body weight) had no effect on the plasma concentration of testosterone 24 h after treatment. If testosterone propionate was given rather than testosterone, the level of LH was significantly reduced (P< 0·001) 24 h after the injection and the concentration of testosterone in the plasma corresponded to that found in the intact adult male pig. Treatment with oestradiol or oestradiol benzoate did not affect the concentration of LH. Orchidectomy and treatment of pubertal male pigs with testosterone propionate resulted in a significantly (P < 0·001) higher concentration of testosterone in the plasma, compared with newborn pigs treated similarly, but the level of LH was unchanged. This suggests that there is a more rapid rate of clearance of testosterone in the newborn than in the pubertal male miniature pig and that the negative feedback of testosterone is not mediated by aromatization in the newborn animal and it declines before or during puberty.
Treatment of newborn intact male and female and gonadectomized male pigs with oestradiol benzoate produced similar variations in the plasma level of oestradiol in all groups of animals. In the female pigs, however, a surge-like release of LH was observed 60–72 h after the injection of oestradiol benzoate, suggesting that the stimulatory feedback mechanism can operate soon after birth and that the response is sexually dimorphic.
EFFECT OF SOMATOSTATIN ON THE CONCENTRATION OF GROWTH HORMONE IN THE PLASMA OF FOETAL SHEEP
Authors: McMILLEN I. C. , JENKIN G. , THORBURN G. D. , ROBINSON J. S. 
Published: December 2008

Nuffield Institute for Medical Research and Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Headington, Oxford, 0X3 9DU
(Received 6 April 1978)
Growth hormone (GH) has been located in the ovine foetal pituitary gland by day 50 of gestation (Stokes & Boda, 1968). The concentration of GH in the plasma of foetal sheep is ten times higher than the postnatal value, increasing from 40 ng/ml on day 100 of gestation to 100–120 ng/ml on day 140 (Bassett, Thorburn & Wallace, 1970). After foetal hypophysectomy, the concentration of GH falls to < 2 ng/ml, indicating that it originates in the foetal pituitary gland (Wallace, Stacey & Thorburn, 1973). Labelled GH does not cross the ovine placenta (Wallace et al. 1973). After sectioning the foetal pituitary stalk, the concentration of GH in the foetal plasma drops to approximately 5 ng/ml (Wallace et al. 1973), which implies that the secretion of GH
STIMULATION OF ADRENAL 5-ENE,3β-HYDROXYSTEROID DEHYDROGENASE BY CORTICOTROPHIN IN VITRO
Authors: LOVERIDGE N. , ROBERTSON W. R. 
Published: December 2008

Division of Cellular Biology, The Mathilda and Terence Kennedy Institute of Rheumatology, Bute Gardens, London, W6 7DW
(Received 24 April 1978)
It is well established (Chayen, Daly, Loveridge & Bitensky, 1976) that segments of guineapig adrenal gland can be maintained in vitro and will respond to low concentrations (0·005– 5·0 pg/ml) of corticotrophin (ACTH). The response measured in the cytochemical bioassay of ACTH is the loss of ascorbate from the zona reticularis (Chayen, Loveridge & Daly, 1972), which is directly related to secretion of cortisol by these segments (Chayen, Bitensky, Chambers, Loveridge & Daly, 1974). However, because both major zones of the adrenal cortex are involved in steroidogenesis (see, e.g., Symington, 1969; Hyatt, Bell, Gould, Tait & Tait, 1976), the lack of a response in the zona fasciculata seems to be anomalous. To test whether the cells of the zona fasciculata in guinea-pig adrenal segments can respond to low concentrations
AN IMPROVED METHOD FOR ESTIMATING CHOLECYSTOKININ IN HUMAN SERUM
Authors: MARSHALL C. E. , EGBERTS E. H. , JOHNSON A. G. 
Published: December 2008

Because of difficulties encountered in setting up radioimmunoassays for cholecystokinin (CCK) a sensitive and reliable biological method for estimating this hormone is still needed. The principles of such a biological technique and an improvement to it have already been described, but the serum levels of CCK reported were high and the technique required further refinement and validation.
The strips of rabbit gall-bladder used to estimate the concentration of CCK increased in sensitivity to standard solutions of CCK over a 6–8 h period before stabilizing, but a single sample of serum increased the sensitivity of the strips of gall-bladder to their maximum immediately. These two problems were eliminated by 'priming' the strips of gall-bladder by exposure to two serum samples before exposure to the standard solutions used for production of a dose–response curve.
Thirdly, it was discovered that some non-peptide substances in serum possessed CCK-like activity; by extracting all the small peptides from serum with dextran-coated charcoal the residual activity could be measured and subtracted from the total CCK activity. Finally, the activity of CCK in the serum increased during processing before freezing. This increase was eliminated by taking the blood samples into aprotinin which has been shown to cause dramatic reduction in CCK activity in some experiments.
When all these factors were taken into account and the technique suitably modified, the mean level of CCK in the serum of ten normal fasting subjects was found to be 28 milli Ivy Dog units/ml (2·4 pmol/ml), which is only one third of that reported previously.
EFFECTS OF HUMAN THYROID-STIMULATING HORMONE AND IMMUNOGLOBULINS ON ADENYLATE CYCLASE ACTIVITY AND THE ACCUMULATION OF CYCLIC AMP IN HUMAN THYROID MEMBRANES AND SLICES
Authors: HOLMES S. D. , DIRMIKIS SUSAN M. , MARTIN T. J. , MUNRO D. S. 
Published: December 2008

The activation of adenylate cyclase and the accumulation of cyclic AMP resulting from the action of human thyroid-stimulating hormone (TSH), long-acting thyroid stimulator (LATS) or LATS-protector (LATS-P) have been investigated in preparations of human thyroid membranes and slices.
Human TSH significantly increased adenylate cyclase activity in membranes from non-toxic goitres whereas LATS and LATS-P had no consistent effect. However, pre-incubation of goitrous membranes with LATS–immunoglobulin G inhibited the effect of TSH on adenylate cyclase. When thyroid membranes were prepared from the glands of patients with Graves's disease neither TSH nor thyroid-stimulating immunoglobulins (TSIg) stimulated adenylate cyclase significantly.
Whether from non-toxic goitres or thyrotoxic tissue, the concentration of TSH needed to induce half of the maximum response was lower in thyroid slices than in membranes. Both LATS and LATS-P significantly stimulated the accumulation of cyclic AMP in slices of goitrous tissue but thyrotoxic tissue slices did not respond.
In goitrous slices, submaximum concentrations of TSH and TSIg caused additive responses in the accumulation of cyclic AMP but TSIg did not increase the maximum response to TSH.
SITE OF BLOOD SAMPLING IN RATS AS A POSSIBLE SOURCE OF ERROR IN HORMONE DETERMINATIONS
Authors: DÖHLER K.-D. , WONG C. C. , GAUDSSUHN D. , VON ZUR MÜHLEN A. , GÄRTNER K. , DÖHLER URSULA 
Published: December 2008

Abteilung für Klinische Endokrinologie, Department für Innere Medizin und Zentrales Tierlabor, Medizinische Hochschule, 3000 Hannover 61, Federal Republic of Germany
(Received 8 May 1978)
The application of a blood sampling technique which by itself has little or no influence on the concentrations of hormones in the circulation of the rat is of utmost importance in experimental hormone research. It has recently been demonstrated that the type of anaesthesia and probably also the site of withdrawal of blood from the body may become critical parameters when the determination of unaltered hormone levels is required (Döhler, von zur Mühlen, Gärtner & Döhler, 1977b). That the site of blood sampling may act as an interfering parameter is questionable, since cage transport, handling and possible differences in the intensity of anaesthesia may also influence the variability of individual hormone levels (Baldwin, Colombo & Sawyer, 1974; Krulich, Hefco, Illner & Read, 1974; Euker, Meites &
ANDROGEN DEPENDENCE OF RAT PROSTATIC 3α-HYDROXYSTEROID DEHYDROGENASE
Authors: MASSA R. , MAS GARCIA M. , MARTINI L. 
Published: December 2008

Department of Endocrinology, University of Milan, Via A. del Sarto 21, 20129 Milan, Italy
(Received 8 May 1978)
It is well established that the rat prostate gland converts testosterone mainly into 5α-androstan-17β-ol-3-one (5α-dihydrotestosterone, 5α-DHT) and to a lesser extent into 5α-androstan-3α,17β-diol (5α-tetrahydrotestosterone, 5α-THT). This occurs, both in vivo and in vitro, through the action of a 5α-reductase and a 3α-hydroxysteroid dehydrogenase system (Baulieu, Lasnitzki & Robel, 1968; Bruchovsky & Wilson, 1968; Gloyna & Wilson, 1969; Kniewald, Massa & Martini, 1971). It has also been recognized that, although the 5α-reduction of testosterone is an irreversible reaction, the reduction of 5α-DHT to 5α-THT is reversible (Becker, Grabosch, Hoffmann & Voigt, 1973; Cresti & Massa, 1977). Consequently, the question has been raised as to whether the biological actions of 5α-THT are attributable to the compound as such or to 5α-DHT. At the anterior pituitary level, 5α-reductase activity is increased by castration and decreased
EFFECTS OF TAMOXIFEN ON PLASMA CONCENTRATIONS OF TESTOSTERONE AND GONADOTROPHINS IN THE MALE RAT
Authors: BARTKE A. , MASON M. , DALTERIO S. , BEX F. 
Published: December 2008

Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545, U.S.A.
(Received 2% March 1978)
Tamoxifen (trans 1-(p-β-dimethylaminoethoxyphenyl)-1,2-diphenylbut-1-ene; ICI 46,474) is both a potent antioestrogen and a weak oestrogen (Harper & Walpole, 1967) and is thought to act by inhibiting the binding of oestradiol to its cytoplasmic receptor (Jordan & Koerner, 1975). Chronic treatment with tamoxifen causes atrophy of the male accessory reproductive glands and the testicular germinal epithelium in the rat (Harper & Walpole, 1967) and the dog (M. Mason, unpublished data), as well as depression of the plasma concentration of testosterone in the latter species (M. Mason & A. Bartke, unpublished data). A direct inhibitory effect of tamoxifen on testicular steroidogenesis was suspected because treatment of female rats with tamoxifen increases, rather than decreases, the plasma concentration of luteinizing hormone (LH; Watson, Anderson, Alam, O'Grady & Heald, 1975). The possibility that an antioestrogen might act directly is of interest since
APPEARANCE OF OESTRONE SULPHATE IN THE ALLANTOIC FLUID OF THE COW
Authors: ROBERTSON H. A. , KING G. J. , CARNEGIE J. A. 
Published: December 2008

Reproductive Physiology Program, Animal Research Institute, Ottawa, Ontario, Canada, K1A 0C6 and * Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
(Received 15 May 1978)
The ability of the conceptus to synthesize oestrogens during the early stages of pregnancy has recently been receiving increasing attention. Among the domesticated species, the day 12 blastocyst of the pig has been shown to be capable of synthesizing oestrogens (Perry, Heap & Amoroso, 1973; Gadsby, Burton, Heap & Perry, 1976) and oestrone sulphate, synthesized as a product of conception, has been shown to be present in the peripheral plasma of the pregnant pig as early as day 17 (Robertson & King, 1974; Robertson, King & Dyck, 1978). In the pregnant ewe, oestrone sulphate has been shown to be the predominant oestrogen in allantoic fluid and to be present in measurable concentrations as early as day 30 (Carnegie & Robertson,
REFRACTORINESS OF THE PITUITARY GLAND AFTER CONTINUOUS EXPOSURE TO LUTEINIZING HORMONE RELEASING HORMONE
Authors: DE KONING J. , VAN DIETEN J. A. M. J. , VAN REES G. P. 
Published: December 2008

The refractoriness of LH release by pituitary glands from intact female rats was studied during stimulation by luteinizing hormone releasing hormone (LH-RH), monobutyryl cyclic AMP+theophylline or potassium in vitro. Various concentrations of LH-RH (0·1, 0·3 and 10 ng/ml) all caused refractoriness within 24 h. Subsequent exposure to a supramaximally active concentration of LH-RH for 6 h also resulted in a depressed response; the degree of inhibition depended on the concentration of LH-RH to which the glands had been exposed previously. Glands made refractory to LH-RH also showed a depressed response to monobutyryl cyclic AMP+theophylline, although these agents by themselves were unable to induce refractoriness. Incubation in medium containing a high concentration of potassium also resulted in the release of LH, which in all respects was similar to that caused by LH-RH. Glands made refractory to LH-RH showed a decreased response to potassium and, conversely, the release of LH in response to LH-RH was reduced after exposure of glands to potassium.
It is concluded that the LH releasing activity of LH-RH, which is mimicked by potassium, deteriorates during continuous exposure to the secretagogue.
SEX RATIO IN UTERO AND THE PLASMA CONCENTRATION OF TESTOSTERONE IN MALE AND FEMALE RAT FOETUSES
Authors: SLOB A. K. , OOMS M. P. , VREEBURG J. T. M. 
Published: December 2008

Department of Endocrinology, Growth and Reproduction, Faculty of Medicine, Erasmus University, P.O. Box 1738, Rotterdam, The Netherlands
(Received 14 June 1978)
Prenatal morphological and behavioural masculinization of female foetuses through exposure to androgen from the testes of male foetuses was first suggested by Clemens (1974). It was reported that female foetuses next to male foetuses in the uterus had a larger ano-genital distance at birth and displayed more (but not statistically significant) mounting behaviour in response to administration of testosterone in adult life than did female foetuses that had not been in such close proximity to foetal male rats. More recently, Gandelman, vom Saal & Reinisch (1977) also reported that in mice, the positions of the female foetuses in the uterus relative to the male foetuses determined the extent to which the female rat was masculinized in terms of both morphology (ano-genital distance at birth) and behaviour (testosterone-induced fighting in
SCREENING OF ABSTRACTS FOR THE FIFTH INTERNATIONAL CONGRESS OF ENDOCRINOLOGY 1976
Authors: SACHS GÜNTHER , VOIGT KLAUS-DIETER , BECK J. C. 
Published: December 2008

Letzter Hasenpfad 63, 6000 Frankfurt 70 a.M., Federal Republic of Germany, * Medical University Clinic, Department of Clinical Chemistry, Martinistrasse 52, 2000 Hamburg 20, Federal Republic of Germany, and † The Robert Wood Johnson Foundation, Suite 310, Parnassus Heights Medical Buildings, 350 Parnassus Avenue, San Francisco, California 94117, U.S.A.
The increase in size of national and international scientific meetings has posed challenges to their efficient and effective organization. In planning the scientific programme, particularly when a process of abstract selection involves the judgement of multiple referees, new procedures should facilitate administration and reduce overall costs. The International Congress of Endocrinology held in Hamburg, Germany, in 1976, utilized a computer-assisted series of steps in handling abstracts and this paper summarizes the observations arising from the processing of over 1500 abstracts. We believe this experience will be valuable to future Congress organizers.
The objective of the process was the preparation of a
REDUCTION OF NON-SPECIFIC SERUM RESPONSES IN HUMAN PITUITARY GONADOTROPHIN RADIOIMMUNOASSAYS
Authors: HUNTER W. M. , BENNIE J. G. 
Published: December 2008

Serum and plasma from human and domestic animals contain variable amounts of non-specific material(s) which may be mistaken for hormone in assays for human LH and FSH, based upon antisera of high sensitivity and hormonal monospecificity. The non-specific response curves are generally, but not invariably, less steep than those of the hormone standards and endogenous homologous hormones. The levels of non-specific intrusion can be of sufficient magnitude to obscure specific estimations seriously, particularly at low hormone levels, unless the assays are designed to minimize this effect.
The non-specific effects could be minimized (but not abolished) by careful optimization of the assays which involved making the response curve as sensitive as possible and incorporating the serum at a final dilution of 1: 2, since further dilution increased the relative contribution of the non-specific substance(s). The optimized assays require only 48 h of total incubation and show a sevenfold increase in the mean concentration of LH between sera from prepubertal children and adults accompanied by a mean threefold difference in the concentration of FSH.
BIOASSAY OF INHIBIN-LIKE ACTIVITY USING PITUITARY CELLS IN VITRO
Authors: DE JONG F. H. , SMITH S. D. , VAN DER MOLEN H. J. 
Published: December 2008

The secretion of follicle-stimulating hormone (FSH) by the pituitary gland appears to be partially regulated by a protein hormone, inhibin, which is produced in the Sertoli cells of the testis and is also present in ovarian follicular fluid (FF). The aim of the present study was to develop a sensitive method for the detection and estimation of inhibin-like activity, using dispersed pituitary cells in culture.
Pituitary cells from adult male rats were dispersed and precultured for 3 days. After renewal of the medium (2 ml), samples to be tested for inhibin-like activity were added and culture was continued for a further 3 days. A dose-dependent suppression of the concentration of FSH in the medium (λ = 0·17–0·22) was observed after addition of FF (0·05–1 μl) or Sertoli cell culture medium (SCCM, 0·05–1 ml). Luteinizing hormone (LH) concentrations were not affected with these doses of FF, but SCCM and higher doses of FF caused a significant increase in the concentration of LH in the medium. During an additional 6 h of culture in the presence of luteinizing hormone releasing hormone (LH-RH), FF and SCCM suppressed the release of both FSH (λ = 0·07–0·11) and LH in a dose-dependent way. Cellular content of FSH, but not of LH, was decreased after these treatments. These results could not be explained by damage to the pituitary cells, by degradation of FSH or LH-RH, or by effects of steroids.
It is concluded that this pituitary cell culture system can be used as a sensitive method for the estimation of inhibin-like activity in FF and SCCM.