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 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.     

Effect of progesterone on male and female sex behavior induced by steroid hormones in adult ovariectomized ewes]

Ovariectomized adult Ewes daily treated with I/M injections of testosterone propionate (10 mg/day) or oestradiol benzoate (200 microgram/day) show male-like sexual behaviour and simultaneously a permanent female receptivity. Additional daily treatment with 100 mg of progresterone results in a rapid decrease in male sexual responses both when Ewes are treated with testosterone and with oestradiol. No effect is observed on the female receptivity. Cyproterone acetate (100 mg/day) given to Ewes in addition to daily injection of testosterone propionate (10 mg/day) has effects similar to those of progesterone. These results show that progesterone has antiandrogen and antioestrogen properties and that this hormone administered at high doses is able to inhibit male activity.     

Sex hormones and concentration of noradrenalin and dopamine in the anterior hypothalamus of castrated rats

Zusammenfassung Die Autoren stellen fest, dass bei Ratten durch Kastration der Gehalt an Noradrenalin und Dopamin im vordern Teil des Hypothalamus ansteigt. Erst hohe Dosen von Östradiol und Progesteron können den Kastrationseffekt wieder zum Verschwinden bringen.

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A previous communication was presented at the XI Meeting of the Sociedad Argentina de Investigacion Clinica, Buenos Aires, 30th October — 2nd November, 1966.

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Fellow of the Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Argentina.     

Effects of estrogen or progesterone on prepuberal ovaries implanted in castrated adult male rats

Résumé Des greffons d'ovaire de rat impubère placés dans la chambre antérieure de l'il du mâle castré, après traitement avec 0,5 mg de dipropionate d'stradiol ou avec deux doses de 1 mg de progestérone, ont montré une évidente ovulation. On interprète ce fait comme dû á l'action des hormones injectées dans le système nerveux central et qui favorisent le mécanisme de l'ovulation.     

The effect of skim milk on plasma cholesterol in rats.

From the 15th day of birth, newborn rats were offered rat chow mixed with water or skim milk. The former also received tap water, the latter skim milk. In the latter group, plasma cholesterol was lowered in 43- and 64-day-old males and in 64-day-old females.     

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.     

Substance P and neurotensin: Opposite effects on plasma cholesterol levels in ovariectomized conscious rats

Summary Intravenous pulse injection of neurotensin produces a significant and dose-dependent increase in plasma cholesterol levels in ovariectomized conscious rats, whereas substance P has opposite effect. 4-Aminopyrazolo (3,4,-d) pyrimidine, (4-APP) also significantly lowers plasma cholesterol. The suppressive effects of both substance P and 4-APP were readily reversed by neurotensin, suggesting that the peptides act on hepatic lipoprotein secretion.Supported by grants from the Indian Council of Medical Research (ICMR), New Delhi. K.R. was recipient of a UGC fellowship.     

Effect of free fatty acids and cholesterol in vitro on liver plasma membrane-bound enzymes

The effect of cholesterol and fatty acid treatment in vitro was tested on rat liver plasma membrane-bound enzymes and lipid fluidity. The observed alterations of membrane fluidity affect both (Na+-K+)-ATPase and Mg2+-ATPase activities but not 5'-nucleotidase; basal adenylate cyclase as well as its hormonal sensitivity were differentially affected by changes of membrane microenvironment.     

Effect of free fatty acids and cholesterol in vitro on liver plasma membrane-bound enzymes

Summary The effect of cholesterol and fatty acid treatment in vitro was tested on rat liver plasma membrane-bound enzymes and lipid fluidity. The observed alterations of membrane fluidity affect both (Na⁺–K⁺)-ATPase and Mg²⁺-ATPase activities but not 5-nucleotidase; basal adenylate cyclase as well as its hormonal sensitivity were differentially affected by changes of membrane microenvironment.This investigation was partially supported by the Italian National Research Council.     

Effect of spironolactone and phenobarbital on the plasma fibrinogen in rats

Résumé Par un dosage de 20 M/100 g poids de spironolactone ou de phénobarbital pendant 3 jours, un niveau de fibrine élevé peut être produit chez des rats. En même temps, l'incorporation des aminoacides C¹⁴ au fibrinogène est aussi intense. Le phénobarbital est dans tous les cas plus efficace que le spironolactone. Dans notre cas, ces médicaments, connus comme inducteurs des enzymes microsomiques, augmentaient la synthèse protéique, enzymatiquement inactive du foie.     

Studies on folate metabolism in castrated rats and those treated with testosterone

Résumé Nous avons recherché l'effect du testostérone sur la capacité de l'acide folique de se transformer en ses formes actives chez le rat intact. Les résultats permettent de suggérer l'hypothèse que le testostérone est en quelque manière interessé à ce processus biosynthétique.