bluuebunny/crossref_metadata_2025_split huggingface dataset:
STEROIDOGENESIS IN ISOLATED RAT ADRENAL GLOMERULOSA CELLS: RESPONSE TO PHYSIOLOGICAL CONCENTRATIONS OF ANGIOTENSIN II AND EFFECTS OF POTASSIUM, SEROTONIN AND [Sar1,Ala8]-ANGIOTENSIN II
Authors: BING R. F. , SCHULSTER D. 
Published: December 2008

Zona glomerulosa cell suspensions with less than 5% fasciculata-reticularis cell contamination were prepared by collagenase digestion of normal rat adrenal capsular tissue. The corticosterone and aldosterone content of such cell suspensions under various conditions were measured simultaneously. Increases in steroid production were observed with physiological concentrations of angiotensin 11 (2 × 10−11 mol/l), with sigmoid log dose-response curves for both corticosterone and aldosterone production (ED50:4 × 10−10 and 8 × 10−10 mol angiotensin II/l respectively). The response to angiotensin II could be abolished by [Sar1, Ala8]-angiotensin II; 50% inhibition was produced by an equimolar concentration of this antagonist. Extracellular potassium ion concentration was shown to affect steroid output dramatically, confirming previous observations and underlining its importance as a physiological regulator of aldosterone secretion. The characteristics of the effect of serotonin, a potent stimulator of steroidogenesis in this system, were also observed. Differences in the maximal responses to angiotensin II and serotonin could not be explained by degradation and probably reflect their different modes of action.
Zona fasciculata-reticularis cell suspensions were prepared in a similar fashion from decapsulated adrenal glands, and showed no increase in steroid production with those concentrations of angiotensin II (2 × 10−11 to 2 × 10−7 mol/l) that stimulated glomerulosa cells. However, angiotensin II amide did increase corticosterone production in isolated fasciculata-reticularis cells at concentrations greater than 2 × 10−5mol/l, as reported by others, whereas angiotensin free acid did not.
It is concluded that this sensitive rat glomerulosa cell suspension will be useful for studying the modes of action of angiotensin II and other stimulators of aldosterone biosynthesis.
INTERACTION OF MORPHINE AND HYPOGLYCAEMIA IN STIMULATING THE RELEASE OF GROWTH HORMONE IN THE RAT
Authors: BLUET-PAJOT M. T. , SCHAUB C. 
Published: December 2008

Unité de Neuroendocrinologie, INSERM – U.159, 2ter rue d'Alésia, 75014 Paris, France
(Received 16 February 1977)
It has been reported by Kokka, Garcia, George & Elliott (1972) and Martin, Audet & Saunders (1975) that morphine stimulates the release of growth hormone (GH) in the rat. Previous studies from this laboratory indicated that another narcoanalgesic, gamma-hydroxybutyrate (GHB), is able to stimulate immunoreactive GH secretion, but the pattern of this response differs markedly from that elicited by morphine (M. T. Bluet-Pajot & C. Schaub, unpublished results). We have also used GHB and eliminated stress effects to demonstrate that GH secretion in the rat can be induced by controlled hypoglycaemia as in primates (Bluet-Pajot, Schaub & Nassiet, 1976).
In the present study we have investigated whether morphine could elicit a GH response under GHB narcoanalgesia, and whether GH secretion induced by spontaneous or provoked hypoglycaemia interfered with this effect.
Automated blood glucose monitoring
EFFECT OF VARIOUS BLOOD SAMPLING TECHNIQUES ON SERUM LEVELS OF PITUITARY AND THYROID HORMONES IN THE RAT
Authors: DÖHLER K.-D. , VON ZUR MÜHLEN A. , GÄRTNER K. , DÖHLER U. 
Published: December 2008

Section of Clinical Endocrinology, Department of Medicine, and Zentrales Tierlabor, Medizinische Hochschule Hannover, 3000 Hannover 61, Germany
(Received 23 March 1977)
The laboratory rat has served many researchers as an excellent model in the study of endocrine mechanisms. However, the great disadvantage of this animal, especially for the endocrinologist, is its sensitivity toward many types of stress (Ducommun, Sakiz & Guillemin, 1966; Neill, 1970; Ajika, Kalra, Fawcett, Krulich & McCann, 1972; Harms, Langlier & McCann 1975). It has been shown that mild stimuli such as handling or cage transport may have significant effects on the release of pituitary, adrenal and thyroid hormones in the male rat (Baldwin, Colombo & Sawyer, 1974; Euker, Meites & Riegle, 1975; Döhler, Gärtner, von zur Mühlen & Döhler, 1977). To obtain accurate information about the genuine state of endogenous hormone circulation, it is of great importance to select blood sampling procedures which have little or
ROLE OF THE PARATHYROID GLANDS IN THE ENHANCEMENT OF INTESTINAL CALCIUM ABSORPTION IN RESPONSE TO A LOW CALCIUM DIET
Authors: FOX J. , SWAMINATHAN R. , MURRAY T. M. , CARE A. D. 
Published: December 2008

SUMMARY
The phenomenon of adaptation of intestinal calcium absorption to changes in dietary calcium has been studied in conscious pigs with Thiry–Vella jejunal loops. The result of decreasing the calcium content of the diet from 1·2 to 0·1% was an increase in the efficiency of the net absorption of calcium from the fluid used to perfuse the jejunal loop; this increase took place 4–6 days after the change in diet. A similar effect was noted in four pigs which had previously been parathyroidectomized and in two thyroparathyroidectomized pigs with thyroxine replacement therapy. The effect seen in the parathyroidectomized animals was not attributable to an increase in the concentration gradient of calcium ions between the jejunal lumen and the blood after the change to the low calcium diet. There was a marked increase in the amount of calcium-binding protein in the mucosa taken from the distal three-quarters of the small intestine of intact pigs fed a low calcium diet. However, after parathyroidectomy, the level of calcium in the diet had no significant effect on the amount of calcium-binding protein in the small intestine.
It is concluded that, in pigs, neither parathyroid hormone nor calcitonin is necessary for intestinal adaptation to a low calcium diet and that, although this adaptation may be mediated by 1,25-dihydroxycholecalciferol, a significant increase in the level of calcium-binding protein in the intestine is only seen when the parathyroid glands are intact.
PREVENTION OF CENTRAL DEFEMINIZATION BUT NOT MASCULINIZATION IN MALE RATS BY INHIBITION NEONATALLY OF OESTROGEN BIOSYNTHESIS
Authors: VREEBURG J. T. M. , VAN DER VAART PAULA D. M. , VAN DER SCHOOT P. 
Published: December 2008

SUMMARY
An inhibitor of aromatization, androsta-1,4,6-triene-3,17-dione (ATD), was administered to newborn male and female rats and various parameters of gonadal and sexual function were examined in adulthood. Males injected with 1 mg ATD on the day of birth (day 1) and on days 3, 5, 10 and 15 postnatally, subsequently (day 55) showed normal male and female copulatory behaviour, but were not able to maintain cyclicity in ovarian transplants. When the ATD was administered by Silastic implants, however, cyclicity in ovarian transplants did occur. Neither form of treatment brought about significant changes in neonatal plasma or testicular testosterone concentrations.
Female rats implanted on day 3 of life with Silastic capsules containing ATD and then given an injection of 0·25 mg testosterone propionate on day 5 subsequently showed normal ovarian function, whereas the controls receiving only testosterone propionate showed persistent vaginal cornification, anovulation and polyfollicular ovaries.
The results support the view that the central conversion of testicular androgens to oestrogens during the neonatal period is necessary to abolish cyclic gonadotrophin release and to suppress female copulatory behaviour.
EFFECTS OF OESTRADIOL AND PROGESTERONE ON THE INDUCTION AND DURATION OF SEXUAL RECEPTIVITY IN CYCLIC FEMALE RATS
Authors: SÖDERSTEN P. , HANSEN S. 
Published: December 2008

SUMMARY
Intact 4-day cyclic rats showed sexual receptivity 24 h after an injection of oestradiol benzoate (OB) on any day of the cycle except on the second day after the display of spontaneous oestrus. Ovariectomy at the time of OB treatment abolished the behavioural response, but receptivity was restored by progesterone. Progesterone treatment early on the day of behavioural oestrus advanced the display of receptivity but did not affect the time at which oestrus ended. Repeated treatment of sexually receptive rats with progesterone did not affect the duration of oestrus. These results show that sexual receptivity in the intact rat cannot occur in the absence of oestradiol and progesterone. The results further suggest that progesterone may not be associated with the mechanisms terminating behavioural oestrus in rats. Treatment with OB on the day of oestrus can prolong the duration of receptivity but only at a higher dosage than that needed for induction of receptivity.
FAILURE OF DIHYDROTESTOSTERONE TO ELICIT SEXUAL BEHAVIOUR IN THE FEMALE CAT
Authors: CERNY VERONICA A. 
Published: December 2008

Laboratory of Anatomy, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.
(Received 28 March 1977)
Testosterones have stimulatory effects on peripheral target tissue and sexual behaviour in male and female rats (Beach, 1942), guinea-pigs (Young, 1961; Diamond & Young, 1963), rabbits (Palka & Sawyer, 1966; Beyer & Rivaud, 1973) and cats (Green, Clemente & de Groot, 1957; Young, 1961; Whalen & Hardy, 1970). 5α-Androstan-17β-ol-3-one (dihydrotestosterone, DHT) has stimulatory effects on peripheral target organs, and like testosterones, a negative feedback effect on the pituitary gland and hypothalamus (Feder, 1971).
No behavioural effects were seen in male or female rats when DHT was injected systemically (Beyer, Morali & Cruz, 1971; Feder, 1971) nor in the male rat when it was administered intracerebrally (Johnston & Davidson, 1972). Many experiments support the hypothesis that only androgens that can be aromatized to oestrogens can elicit sexual behaviour and
PITUITARY-ADRENAL RESPONSE TO ETHER STRESS IN THE NEONATAL RAT
Authors: TANG F. , PHILLIPS J. G. 
Published: December 2008

Wolfson Laboratory for Research in Gerontology, Department of Zoology, University of Hull, Hull, HU6 7RX
(Received 20 June 1977)
A relative lack of adrenocortical responsiveness to stress has been described in the rat during the period from day 2 to about day 16 of neonatal life (Schapiro, Geller & Eiduson, 1962; Levine, Glick & Nakane, 1967; Corte & Yasumura, 1975) and the reports to date seem to implicate a lack of response of the pituitary gland as the primary cause (Zarrow, Philpott & Denenberg, 1968; Donovan, 1970; Corte & Yasumura, 1975). Since very little work has been done on the response of the pituitary gland to stress in the neonatal rat, the present study was undertaken.
Female Sprague–Dawley rats weighing 300 g were housed at 22 °C with a light : darkness cycle of 12 : 12 h. Mated female rats were isolated on day 1 of pregnancy, and after
EFFECT OF OESTRADIOL INFUSION ON PLASMA GONADOTROPHINS AND OVARIAN ACTIVITY IN PROGESTERONE-PRIMED AND UNPRIMED ANOESTROUS EWES
Authors: PANT H. C. 
Published: December 2008

Plasma gonadotrophin and ovarian responses to physiological infusions of oestradiol were examined in anoestrous ewes with and without progesterone priming. Intravenous infusion of oestradiol (1 μg/h) for 24 h followed at 96 h by a second infusion for 12 h (low dose) resulted in simultaneous increases in LH and FSH of magnitude and duration similar to those of ewes at natural oestrus. Infusions of 3 μg/h for 16 h, and again at 96 h for 4 h (high dose) resulted in similar gonadotrophin peaks. Endoscopy revealed that only two out of eight ewes had ovulated despite increased ovarian activity and surges of plasma gonadotrophins.
Other anoestrous ewes were primed with 25 mg progesterone daily for 12·5 days before similar infusions of oestradiol on day 15. In the presence of very low plasma progesterone concentrations (< 1·0 ng/ml) at the onset of infusion, there was no pituitary response to the infusion of a low dose of oestradiol but the gonadotrophins were released after the second high-dose infusion.
Progesterone inhibited the positive feedback on both gonadotrophins but not the negative feedback on FSH. Ovulation occurred in all four ewes which had been progesterone-primed and infused with a high dose of oestradiol.
PITUITARY-ADRENAL RESPONSE IN MALE RATS SUBJECTED TO CONTINUOUS ETHER STRESS AND THE EFFECT OF DEXAMETHASONE TREATMENT
Authors: TANG F. , PHILLIPS J. G. 
Published: December 2008

Wolfson Laboratory for Research in Gerontology, Department of Zoology, University of Hull, Hull, HU6 7RX
(Received 5 April 1911)
Jones, Brush & Neame (1972) reported that the level of adrenocorticotrophin (ACTH) in the plasma returned to the control value as early as 10 min after sham adrenalectomy. In contrast, Cook, Kendall, Greer & Kramer (1973) observed no decline in the level of radioimmunoreactive ACTH in the plasma until 40 min after the onset of a 2·5 min ether stress. Furthermore, the stress levels of ACTH were maintained for 2 h in animals subjected to continual ether stress. Therefore, the levels of both ACTH and corticosterone in sequential samples of plasma from control and dexamethasone-treated rats were measured, in order to see whether a negative feedback mechanism, that acts on the pituitary gland as the level of corticosterone increases, operates even in the presence of continuous stress.
Blood samples were taken
INHIBITION OF NEUROHYPOPHYSIAL HORMONE RELEASE FROM THE ISOLATED RAT NEURAL LOBE BY FERROUS CHLORIDE IN THE INCUBATION MEDIUM
Authors: DYBALL R. E. J. , WRIGHT R. J. 
Published: December 2008

A. R. C. Institute of Animal Physiology, Babraham, Cambridge, CB2 4AT
(Received 12 April 1977)
Both electrical stimulation with steel microelectrodes and injection of iron salts into the preoptic area lead to an increased concentration of luteinizing hormone (LH) in the plasma and ovulation (Everett & Radford, 1961; Dyer & Burnet, 1976).
Initially, iron salts were thought to excite nerve cells but Fe2+ and Fe3+ ions, like most cations, when applied to nerve cells by micro-iontophoresis, inhibit firing (Dyer & Burnet, 1976). Dyer & Burnet (1976) proposed a number of alternative explanations for the electrochemical stimulation of ovulation. They suggested that ferrous or ferric ions might kill or damage some neurones and the resulting cell disruption might lead in turn to the liberation of a sufficient quantity of luteinizing hormone releasing hormone (LH-RH) into the hypophysial portal vessels to cause a surge of LH. Alternatively, ovulation might be stimulated by
GROWTH AND URINE OSMOLARITY IN YOUNG BRATTLEBORO RATS
Authors: DLOUHÁ H. , KŘEČEK J. , ZICHA J. 
Published: December 2008

Institute of Physiology, Czechoslovak Academy of Sciences, Prague, Czechoslovakia, 142 20
(Received 18 April 1977)
If Brattleboro rats, homozygous (DI) and heterozygous (non-DI) for diabetes insipidus are deprived of water, no difference in urinary osmotic pressure can be detected between the two genotypes before 14 days of age Dlouhá, Křeček & Zicha, 1976). This may arise from a shortage of vasopressin in non-DI rats until week 3 after birth, as has been demonstrated in rats of the Wistar strain (Křeček, Dlouhá & Křečková, 1961). We have attempted to detect differences in osmoregulation in DI and non-DI rats before diabetes insipidus is manifest.
Samples of urine were obtained from 147 young Brattleboro rats by perineal stimulation. In 10- and 14-day-old animals, all procedures were done at 30 °C. Dehydration was induced in 10-, 14-, 18- and 22-day-old rats by water deprivation for 6 h; water diuresis was induced in 14-, 19-
OESTROGEN-INDUCED PROTEIN IN RAT MAMMARY TUMOUR AND UTERUS
Authors: MAIRESSE N. , HEUSON J. C. , GALAND P. , LECLERCQ G. 
Published: December 2008

Biology Unit, Institute of Interdisciplinary Research, Free University of Brussels, 115 B Waterloo, 1000-Brussels, Belgium and *Service de Médecine et Laboratoire d'Investigation Clinique, Institut J. Bordet, 1000-Brussels, Belgium
(Received 19 April 1977)
We wish to report evidence for the early induction by oestradiol-17β of a protein in mammary tumours induced in Sprague–Dawley rats by 7,12-dimethylbenz(a)anthracene (DMBA). The protein appears to be analogous to the oestrogen-induced protein first discovered in the rat uterus by Notides & Gorski (1966) and widely known as 'induced protein' (IP). Induction of IP by oestradiol-17β has been demonstrated in rodents in several tissues of the female genital tract that are targets for oestrogens (Katzman, Larson & Podratz, 1971; Katzenellenbogen & Leake, 1974; Dupont-Mairesse & Galand, 1975) and correlated with the rate of nuclear accumulation of oestrogen receptors (Katzenellenbogen & Gorski, 1972; Katzenellenbogen, 1975). Therefore, the search for induction of IP in DMBA-induced mammary tumours containing oestrogen
ADRENAL AND GONADAL GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITY IN AGEING RATS
Authors: LEATHEM J. H. , APPEL N. M. 
Published: December 2008

Bureau of Biological Research, Rutgers University, New Brunswick, New Jersey 08903, U.S.A.
(Received 24 March 1977)
Dehydrogenase enzyme activity linked to NADP has been implicated in the regulation of steroidogenesis in the adrenal gland and ovary (McKerns, 1964, 1965). Furthermore, glucose6-phosphate dehydrogenase (G6PD) activity increases after trophic hormone stimulation, suggesting a metabolic role in the stimulated cells (Castracane & Leathern, 1976). However, little consideration has been given to G6PD as a metabolic marker in steroidogenic organs in relation to ageing. Trout (1974) found G6PD activity to be greater in the adrenal glands of female than of male Wistar rats, but observed no change with age up to 19 months, whereas Stewart & Hunter (1969) recorded a decline in both adrenal and ovarian G6PD activity in 24-month-old Long-Evans rats. A re-examination of G6PD activity in the adrenal glands, testes and ovaries (which exhibit a decline in the formation of follicles: Leathem
EFFECTS OF PIMOZIDE AND BROMOCRIPTINE ON THE PROLIFERATION OF RAT PITUITARY PARS INTERMEDIA CELLS
Authors: RYCHTER J. , STEPIEŃ H. 
Published: December 2008

Department of Experimental Endocrinology, Institute of Endocrinology, Medical Academy of Łódź, Dr. Sterling str. 3, 91-425 Łódź, Poland
(Received 31 May 1977)
The secretory function of the intermediate lobe of the pituitary gland is under hypothalamic control (Howe, 1973; Hadley & Bagnara, 1975). Penny, Thody, Tilders & Smelik (1977) have suggested that the synthesis and release of melanocyte-stimulating hormone (MSH) is mediated by dopaminergic neurones which make synaptic contact with secretory cells in the pars intermedia (Björklund, Moore, Nobin & Stenevi, 1973). We have attempted to examine whether the dopaminergic mechanism is also involved in the control of the mitotic activity of the pars intermedia cells and have studied the effects of pimozide, a dopamine receptor blocker (Anden, Butcher, Corrodi, Fuxe & Ungerstedt, 1970) and 2-bromo-α-ergocriptine (bromo-criptine), a dopamine receptor agonist (Loew, Vigouret & Jaton, 1976) on the mitotic activity of the pars intermedia of the rat pituitary gland.
Twenty-three
EFFECT OF ACTIVE IMMUNIZATION OF THE CYCLIC EWE AGAINST OESTRADIOL-17β
Authors: RAWLINGS N. C. , KENNEDY S. W. , HENRICKS D. M. 
Published: December 2008

SUMMARY
Six mature cyclic ewes were immunized against an oestradiol-17 β-6-oxo-carboxy-oxime-bovine serum albumin conjugate (oestradiol–protein conjugate). Injection of the conjugate began on day 2 of an oestrous cycle, and subsequent booster injections were given on days 12, 22, 32, 62 and 102.
Six control ewes treated with carrier emulsion alone continued to display regular oestrous cycles, whereas the six immunized ewes failed to return to oestrus after the initiation of treatment. The six immunized ewes failed to ovulate by day 22 of the oestrous cycle in which treatment began, and the preovulatory surge of LH did not occur, although the basal concentration of LH in the jugular plasma rose. The luteal phase of the oestrous cycle in which the first injection of the conjugate was made was normal and three out of six immunized ewes showed typical changes in the cervical mucus at the time of the next expected oestrus. The capacity of the plasma to bind oestradiol-17β rose above the control level after the first booster injection and continued to increase until the end of the experiment, 118 days after the initial treatment. The only significant cross-reactions of the antisera were with oestrone.
The concentration of LH in the plasma rose in parallel with the antisera titres and towards the end of the experiment, a definite episodic pattern of LH secretion was indicated. In immunized ewes the concentration of oestradiol-17β in the plasma increased, reaching 286 ± 36 (s.e.m.) pg/ml, a level far in excess of that found in the normal cyclic ewe. The concentration of progesterone in the circulation was raised for a variable period of time in all immunized ewes between days 30 and 118 after the initial treatment.
LUTEINIZING HORMONE RESPONSIVENESS TO LUTEINIZING HORMONE RELEASING HORMONE IN THE ADULT GUINEA-PIG: DIRECT OVARIAN INVOLVEMENT
Authors: TER HAAR M. B. 
Published: December 2008

SUMMARY
The effects of intravenous injection of synthetic luteinizing hormone releasing hormone (LH-RH) on the release of LH and FSH have been studied in the adult guinea-pig. In all the experiments the secretion of FSH was apparently unaffected by administration of LH-RH. The release of LH was log dose-dependent over the range 0·5–50 μg LH-RH.
During the female cycle, the maximum increment in the concentration of LH after a single i.v. injection of 0·5 μg LH-RH decreased progressively from day 1 to day 13. Double or triple injections of 1 μg LH-RH at 1 h intervals produced no potentiation on day 3 but progressively greater LH responses occurred on days 7, 10 or 13 of the oestrous cycle. Ovariectomy immediately before the first injection of LH-RH on day 7 blocked the potentiated response to subsequent injections, whereas ovariectomy immediately before the second injection still permitted this potentiation. These results suggest that there is direct ovarian involvement in the potentiated response to LH-RH observed during the later part of the guinea-pig oestrous cycle.
Infusion of LH-RH (1 μg over 200 min) produced a potentiated release of LH in female guinea-pigs on day 7 (but not on day 3) of the oestrous cycle after a delay of 1·5 h. It is proposed that there are two 'pools' of LH in the pituitary gland of the female guinea-pig and that the second pool is 'activated' consequent upon previous hypophysial stimulation of secretion from an ovary containing adequately developed follicles.
PROSTAGLANDIN PRODUCTION BY INTRA-UTERINE TISSUES FROM PERIPARTURIENT SHEEP: USE OF A SUPERFUSION TECHNIQUE
Authors: MITCHELL M. D. , FLINT A. P. F. 
Published: December 2008

SUMMARY
A technique for the continuous superfusion of small tissue samples in vitro has been applied to the study of prostaglandin production by ovine intra-uterine tissues. Basal and oxytocin-stimulated production of prostaglandins was studied at 120–125 days of pregnancy and after dexamethasone-induced delivery. In general, the relative rate of prostaglandin production by tissues was: foetal cotyledon = maternal cotyledon>myometrium and in quantitative order the prostaglandins produced were prostaglandin E (PGE) > prostaglandin F (PGF) = 13,14-dihydro-15-oxo-prostaglandin F (PGFM). Considerable variation was found between the rates of prostaglandin production in individual sheep. Oxytocin had no effect on the production of prostaglandins by tissues obtained before labour but myometrium and maternal cotyledon obtained at delivery exhibited a significant increase in production of PGE and PGF (though not PGFM) in response to oxytocin. Administration of arachidonic acid increased the production of PGE and PGF by the foetal cotyledon.