Time-dependence of estradiol effects on protein synthesis in the rat neurohypophysis.

The incorporation of 3H-leucine into neurohypophyseal proteins was measured in vitro, 24 h after the administration of a single dose of estradiol (0.3 mug) to castrated female rats. Estradiol treatment caused a significant increase of 3H-leucine incorporation into proteins of the posterior lobe. The effects of estradiol depended largely upon time injection. Rats injected at 06.00 h, i.e., at the end of the dark period exhibited a 74% increase in protein synthesis, whereas rat injected at 14.00 h, i.e., at the middle of the light period only showed a 30% of increase.     

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.     

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.     

An early effect of testosterone propionate upon hypothalamic function in the neonatal rat

Rats treated neonatally with testosterone propionate exhibit a reduced uterine growth response to estradiol administration prepubertally. This androgen-induced impairment is the consequence of developmental effects on both the ovary and the hypothalamic-pituitary complex, although the latter is the more sensitive.     

Consumption of vitamin A in intact and castrated rats. Relation to tocopherol and cytochrome P 450]

There are significant differences between castrated and non castrated male Rats in regard to vitamine A hepatic storage and plasma level. Cytochrom P 450 levels are the same in both groups. Those results are discussed.     

Hormonal induction of steroid sulphatase in the mouse

By comparing steroid sulphatase levels per se, and also ratios to alpha-galactosidase, in 6 sets of mice - normal females, entire and castrated males both with and without exogenous testosterone administration - we obtained support for the contention that induction of this enzyme is in part controlled by male hormones.     

Temporal effects of ACTH,indomethacin and 7-oxa-13-prostynoic acid upon glucocorticoid production by the human adrenal

Summary Indomethacin or 7-oxa-13-prostynoic acid does not alter basal adrenal cortisol output. Preincubation in either, depresses subsequent ACTH-stimulated cortisol output below ACTH alone and controls. Either inhibitor following ACTH preincubation blunts normal ACTH-stimulated cortisol production.     

Effects of insulin on plasma fibrinogen levels in rats submitted to tissue injury or ACTH administration.

Insulin is necessary to produce an increase of plasma fibrinogen in rats submitted to tissue injury or ACTH administration. This increase is more significant when endogenous or exogenous excess of insulin is present, while in uninjured rats the absence or excess insulin does not modify plasma fibrinogen.     

Effects of stress and adrenocorticotrophin administration on plasma corticosterone levels at different stages of pregnancy in the mouse.

Stress or administration of ACTH to pregnant mice gave rise to much higher plasma corticosterone levels in the second half of pregnancy than in the first half, suggesting that there may be increased adrenal sensitivity to ACTH or decreased metabolism of corticosterone during the second half of pregnancy.     

Effects of insulin on plasma fibrinogen levels in rats submitted to tissue injury or ACTH administration

Summary Insulin is necessary to produce an increase of plasma fibrinogen in rats submitted to tissue injury or ACTH administration. This increase is more significant when endogenous or exogeneous excess of insulin is present, while in uninjured rats the absence or excess of insulin does not modify plasma fibrinogen.     

Effects of stress and adrenocorticotrophin administration on plasma corticosterone levels at different stages of pregnancy in the mouse

Summary Stress or administration of ACTH to pregnant mice gave rise to much higher plasma corticosterone levels in the second half of pregnancy than in the first half, suggesting that there may be increased adrenal sensitivity to ACTH or decreased metabolism of corticosterone during the second half of pregnancy.     

Hormonal induction of steroid sulphatase in the mouse

Summary By comparing steroid sulphatase levels per se, and also ratios to -galactosidase, in 6 sets of mice — normal females, entire and castrated males both with and without exogenous testosterone administration — we obtained support for the contention that induction of this enzyme is in part controlled by male hormones.     

Effect of orchidectomy and estradiol on acetylcholinesterase activity in rat brain areas and adenohypophysis

Summary Orchidectomy plus estradiol administration decreased acetylcholinesterase activity in the rat cerebral cortex and mesencephalon, while in the amygdala it was increased. In the adenohypophysis, orchidectomy increased enzyme activity, but subsequent estradiol treatment decreased it. The hypothalamus did not respond to either manipulation.     

Effect of orchidectomy and estradiol on acetylcholinesterase activity in rat brain areas and adenohypophysis

Orchidectomy plus estradiol administration decreased acetylcholinesterase activity in the rat cerebral cortex and mesencephalon, while in the amygdala it was increased. In the adenohypophysis, orchidectomy increased enzyme activity, but subsequent estradiol treatment decreased it. The hypothalamus did not respond to either manipulation.     

Activation of the pituitary-adrenal axis by nipple suction in the lactating rat]

The response of the pituitary-adrenal axis to suckling in lactating Rats is dependent on two factors: 1. a psychic factor, which is identical by its effects to the psychological stress of the strange environment (transitory increase of plasma corticosterone and no significant modification of the content of ACTH in the two lobes of the pituitary); 2. a specific factor namely the stimulation of the nipples, which is distinguishable from the psychic factor by a longer release of corticosterone by the adrenals and a durable and significant decrease of the content of ACTH in the pars distalis.     

Anti-estrogen inhibition of testosterone-stimulated aggression in mice

Testosterone-stimulated intermale aggression in castrated mice can be reversibly inhibited by anti-estrogen administration suggesting that estrogen formation and actions in the brain may be required for testosterone's behavioral actions.     

Age-and sex-related development of ACTH in the pars distalis and neurointermedia of rat pituitary]

The content of ACTH of the pars distalis and neurointermedia of the pituitary of adult Rats is higher in the male than in the female. This differenciation of content, according to sex, appears at puberty at the site of pars distalis; it only appears around the 60th day of life at the site of the pars intermedia. The androgens seem to be responsible for the higher percentages observed in the males.     

Mechanism of induction of tyrosine in rat liver by phenothiazine derivatives and related chemical compounds]

Increase of hepatic tyrosine-alpha-ketoglutarate transaminase is observed in Rats (Wistar strain) after intraperitoneal administration of tricyclic compounds (phenothiazin and related structure derivatives). This is an induction process: actinomycine D inhibits this effect. This action is not mediated by glucocorticoids: induction persists in adrenalectomized Rats. The mechanism of action is different too: additive effects are found after simultaneous injection of glucocorticoid and tricyclic drug.