Prenatal stress and postnatal androgen: effects on reproduction in female rats

Heat-resistant stress applied to pregnant rats during the last trimester disrupts oestrus cycles in female offspring and alters adrenal, ovarian and uterine weights at autopsy. Sexual receptivity is left intact. Prenatal stress may operate by increasing exposure of fetal females to androgens in utero.     

Prenatal stress and postnatal androgen: Effects on reproduction in female rats

Summary Heat-restraint stress applied to pregnant rats during the last trimester disrupts oestrus cycles in female offspring and alters adrenal, ovarian and uterine weights at autopsy. Sexual receptivity is left intact. Prenatal stress may operate by increasing exposure of fetal females to androgens in utero.     

Radioimmunoassay of some hormones simultaneously measured in serum and breast cyst fluid

Blood and breast cyst fluid were drawn simultaneously for hormonal determination. There was no difference between serum and cyst fluid values of PRL and TSH. A significant difference was noted for LH (p less than 0.01) and FSH (p less than 0.05), serum concentrations being higher than cyst fluid concentrations.     

Radioimmunoassay of some hormones simultaneously measured in serum and breast cyst fluid

Summary Blood and breast cyst fluid were drawn simultaneously for hormonal determination. There was no difference between serum and cyst fluid values of PRL and TSH. A significant difference was noted for LH (p<0.01) and FSH (p<0.05), serum concentrations being higher than cyst fluid concentrations.The authors are indebted to Miss J. Meister, E. Dullaert and J. Beck for their skillful technical help. We are also indebted to the National Institutes of Health, NIAMDD and the World Health Organization, International Laboratory for Biological Standards.     

Effect of sex hormones on uric acid metabolism in rats.

The effects of sex hormones on purine metabolism were investigated in rats. No influence on purine synthesis was shown by the injection of estrogen and androgen. The plasma urate levels were significantly lowered from 2.43 +/- 1.04 mg/100 ml to 1.53 +/- 0.57 mg/100 ml by the injection of progesterone. Urinary excretion of uric acid plus allantoin was slightly reduced. These results suggested that progesterone may influence age and sex differences in human plasma urate levels.     

Effects of sexual hormones on gonadotrophin secretion in prepuberal female rats

Resumen Los estrógenos ejercen sobre la rate hembra un efecto de retroalimentación negativo sobre la secreción de gonadotrofinas a los 20 días de edad y un efecto positivo a los 28 días de edad. La testosterona inhibió la secreción de gonadotrofinas en ratas de 20 días, pero no tuvo efecto a los 28 días de edad. En los animales androgenizados al nacer ambas hormonas inhiben la secreción de gonadotrofinas a los 20 y a los 28 días de edad.

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Supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas. Repùblica Argentina.     

Effect of sex hormones on plasma cholesterol in castrated and noncastrated male rats

Summary The administration of estradiol to both castrated and noncastrated male rats was associated with significantly increased plasma cholesterol levels as compared to controls, the estradiol in the noncastrated rats overriding the tendency of testosterone to lower plasma cholesterol.Acknowledgement. This work was supported by USPHS Grant NHLBI 17721.     

Effect of sex hormones on plasma cholesterol in castrated and noncastrated male rats

The administration of estradiol to both castrated and noncastrated male rats was associated with significantly increased plasma cholesterol levels as compared to controls, the estradiol in the noncastrated rats overriding the tendency of testosterone to lower plasma cholesterol.     

Insect hormones in vertebrates: Anabolic effects of 20-hydroxyecdysone in Japanese quail

Ecdysteroids are hormones controlling cell proliferation, growth and the developmental cycles of insects and other invertebrates¹. They are occasionally present in various unrelated plants for no apparent reason; no phytohormonal function has yet been identified. In certain cases, ecdysteroids are accumulated to high levels in leaves, roots or seeds. Some ecdysteroid-containing plants have been known as medicinal plants for centuries. One of them,Leuzea carthamoides Iljin (Asteraceae), growing in Central Asia, contains 0.4% ecdysteroid in dry roots and 2% in seeds. A pharmacological preparation from this plant, Ecdisten, is already available as a commercial preparation for its anabolic, tonic and other effects, for medical use (review²). It remained problematic, however, whether ecdysteroids were truly responsible for these effects, becauseLeuzea contains a number of other biologically active compounds in addition to ecdysteroids. We extracted and purified ecdysteroids from the seeds ofLeuzea. With 6 g of 96% 20-hydroxyecdysone (20E), we made a large-scale feeding assay with Japanese quail to find out whether ecdysteroid alone could duplicate the anabolic effects of the seeds. We found that the 96% ecdysteroid increased the mass of the developing quails in a dose-dependent manner, with the rate of increase proportional to the ecdysteroid content in the seeds; there was a 115% increase in living mass with 100 mg kg^–1 of pure 20E compared with 109.5% increase with 100–180 mg kg^–1 20E equivalents in the seeds. We conclude that the plethora of growth-promoting, vitamin-like effects induced in vertebrates byLeuzea is mediated by ecdysteroids.     

The effect of various diuretic agents on renal electrolyte and urea concentration gradients in rats

Zusammenfassung Die Konzentrationsgradienten von Na+und Harnstoff im Rattennierengewebe werden durch intravenöse Applikation von Merallurid, Salyrgan und Hydrochlorothiazid nicht beeinflusst. Die Änderung des Na-Gradienten nach Aminophyllin hängt von der Injektionszeit ab. Acetazolamid-, Chlorothiazid- und Furosemid-Injektion führt jedoch zur Senkung oder zum Verschwinden eines Na-Gradienten. Die Kaliumkonzentration in der Rinde und Papilla wird durch Hg- und Sulfonamid-Diuretica erniedrigt.     

Kinins in cerebrospinal fluid: reduced concentration in spontaneously hypertensive rats

Rat cerebrospinal fluid contains peptides which displace radiolabeled bradykinin from its specific antibodies. Two peptides which showed the same retention time as kallidin and bradykinin in a reverse phase high pressure liquid chromatography system were detected in cerebrospinal fluid of rats. The concentration of radioimmunologically detected kinins in the cerebrospinal fluid of spontaneously hypertensive rats of the Okamoto strain was lower than that of the Wistar Kyoto control rats.     

Lethal effects of heat on bacterial physiology and structure

High temperatures have profound effects on the structural and physiological properties of sporulating and non-sporulating bacteria, with membranes, RNA, DNA, ribosomes, protein and enzymes all affected. Nevertheless, it is apparent that no one single event is responsible for cell death. The induction of intracellular heat-shock proteins and the activation of extracellular alarmones in vegetative cells exposed to mildly lethal temperatures are important cell responses. In bacterial spores, several factors contribute to the overall resistance to moist (wet) and dry heat; the latter, but not the former, induces mutations. Heat resistance develops during sporulation, when spore-specific heat-shock proteins are also produced. Heat sensitivity is regained during germination of spores.     

Intraventricular administration of isoproterenol inhibits both heat production and heat loss mechanisms in rats

Summary At an ambient temperature (T_a) of 8°C, intraventricular administration of isoproterenol inhibited metabolic heat production and led to hypothermia in rats. In contrast, at a T_a of 22°C and of 30°C, isoproterenol decreased cutaneous circulation and led to hyperthermia. The data indicate that isoproterenol inhibits both heat production and heat loss mechanisms in rats.This work was supported by a grant from the National Science Council of the Republic of China. The authors are grateful to Dr C.Y. Chai for pertinent advice.     

The action of sex hormones on endometrial secretion in spayed rats sensitized to oestradiol

Zusammenfassung Ligatur der distalen Enden der Uterushörner von adulten, kastrierten, mit Östradiol sensibilisierten Ratten hat eine Ansammlung der uterinen Flüssigkeit zur Folge. Die Wirkung von Östradiol, Testosteron und Progesteron auf die Eigenschaften dieser Flüssigkeit wurde untersucht. Während Östradiol in verschiedenen Dosen keinen signifikanten Effekt aufweist, zeigt Testosteron und besonders Progesteron eine ausgeprägte Wirkung. Sie reduzieren die Menge der Flüssigkeit, erniedrigen das pH und steigern die Viskosität. Diese Veränderungen könnten für die Hemmung der Fertilität durch diese Substanzen von Bedeutung sein.     

Plasma catecholamines in conscious rats: Influence of sodium,stress and heredity

Summary Plasma catecholamines are increased in sodium-loaded rats under both resting and stress conditions. Under stress, Na⁺ resistant rats have lower plasma catecholamines than salt-sensitive ones.Supported in part by grants from Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS) and Délégation Générale à la Recherche Scientifique et Technique (DGRST).     

Nicotine and ascorbic acid effects on cold-restraint ulcers in rats

Summary Rats were orally administered 1-ascorbic acid, nicotine, 1-ascorbic acid and nicotine, or distilled water for 10 days. Following this treatment they were fasted for 24 h and then restrained in a cold environment for 2h. Nicotine alone produced significantly more gastric ulcers than any other treatment. 1-Ascorbic acid increased ulceration relative to controls. The combined effects of 1-ascorbic acid and nicotine resulted in reduced ulcer incidence and severity. It appears that 1-ascorbic acid and nicotine do not act synergistically to augment stress-induced gastric ulcer. Supported by Natural Sciences and Engineering Research Council of Canada grant No. A 6312.