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.     

Two-step purification of estradiol calf uterine cytosol receptor]

The use of two affinity chromatography methods: heparin-Ultrogel and estradiol 7 alpha-(CH2)3-poly (alanine-lysine)-agarose, allows us to purify the calf uterine estradiol cytosol receptor with a 20% recovery. Electrophoresis under denaturing conditions allows us to estimate its molecular weight as 70 000 dalton.     

Inhibitory action of estradiol on testosterone production in rat embryo]

Embryos from Rats given an injection of 0,5-1 mg of oestradiol benzoate on days 17--19 of pregnancy show a 3--4-fold reduction in their testicular testosterone content with respect to the control embryos, 24--48 hrs later. OEstradiol most likely acts by inhibiting LH secretion, which in turn results in a lowered testosterone production.     

Production and detection of antibody against estradiol receptor in the calf uterus. Interaction with the estrogen receptor from the hen oviduct]

The antibodies against estrogen receptor were obtained after injecting Rabbits with a cytoplasmic receptor fraction isolated from Calf uterus. The estrogen receptor was partially proteolysed by the action of trypsin and subsequently purified by affinity chromatography (purification 4,000 to 10,000 fold, to a purity of 5-20%). The affinity of the antibody for the proteolysed receptor is KD approximately 1 nM and serum titres have reached values of approximately 50 nM. The values remained constant after the third injection. Preliminary results indicate that the antibody has approximately the same affinity for "native" cytoplasmic estrogen receptor from Calf uterus, as well as for the "trypsinized" forms of estrogen receptor isolated from Calf uterine cytosol and Hen oviduct nuclei.     

The influence of estradiol on the distribution of exogenous cholesterol-4-C14 in the rat

Zusammenfassung Vorbehandlung mit Östradiolbenzoat führte bei kastrierten männlichen Ratten zu einer verminderten Aufnahme von oral zugeführtem Cholesterin-4-C¹⁴ in die Aorta. Bei kastrierten wie auch bei intakten Tieren war nach Östrogenbehandlung die Aufnahme von markiertem Cholesterin in die Leber erhöht. Durch Analyse der Faeces liess sich nachweisen, dass Östrogenbehandlung sowie Kastration die Sterolausscheidung beschleunigt.     

Long term effects of neonatal hypothyroidism on pituitary estradiol binding sites in the female rat

Two months after recovery from a perinatal hypothyroidism (PTU), the total amount of pituitary estradiol binding sites (EBS) was still dramatically reduced, but the actual concentration of EBS had returned to control levels.     

Effect of spermine on the kinetics of estradiol hydroxylation by rat liver microsomes

Résumé L'addition de spermine au microsomes du foie de rats femelles modifie leK _m du système enzymatique qui transforme 1'estradiol en 2-hydroxyestradiol et aussi en des produits aqueux. La nouvelle valeur resemble à celle qu'ont trouve avec des rats mâles, mais leV _max de la réaction reste inchangé. L'action de la spermine dans ce système est discutée.     

A biphasic effect of estradiol on serotonin metabolism in rat pineal organ cultures

Summary Physiological amounts of estradiol (1 nM) significantly increased serotonin, conversion to melatonin and 5-methoxytryptophol by rat pineal glands in organ culture whereas larger, pharmacological, doses (i.e. 1000 nM) impaired it significantly. The stimulatory but not the inhibitory effect of estradiol was blocked by the simultaneous addition of puromycin in the culture medium.This study was supported by grant No. 6638 from the Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET), Argentina.