Progestagen-dependent effect on some plasma proteins during oral contraception.

Seventeen healthy women received a combination of 0.030 mg of ethinyl estradiol and 0.150 mg of levonorgestrel or a combination of 0.

Receptor binding of allylestrenol, a progestagen of the 19-nortestosterone series without androgenic properties.

Allylestrenol (17 alpha-allyl-17 beta-hydroxy-4-estren) is an orally active progestagen of the 19-nortestosterone series resembling progesterone since it has no detectable androgenic activity in animal studies and in the human. In the present study, the affinity of its 3-keto metabolite for the transformed progesterone receptor in intact MCF-7 cells was about twice that of progesterone and cyproterone acetate and about 2-3 times less than that of medroxyprogesterone acetate and norethisterone, reflecting the known progestational activity of allylestrenol. The affinity of 3-ketoallylestrenol for the transformed androgen receptor in intact MCF-7 cells was weak (like other progestagens lacking androgenic activity or possessing anti-androgenic activity) and lower than that of weakly androgenic progestagens.

Comparison of the receptor binding properties of nandrolone and testosterone under in vitro and in vivo conditions.

Previous in vitro binding studies with androgen receptors in rat seminal vesicles (Toth M. and Zakar T., J.

Metabolism and receptor binding of nandrolone and testosterone under in vitro and in vivo conditions.

The metabolism and receptor binding of nandrolone (N) and testosterone (T) were studied under in vitro and in vivo conditions. The results of both in vitro incubation studes with 3H-N and 3H-T in tissue homogenates from rats and in vivo infusion studies with 3H-N and 3H-T in conscious rats show the importance of the enzymes 5 alpha-reductase and 3 alpha/beta-hydroxysteroid-oxidoreductases in the prostate and the importance of the enzyme 17 beta-hydroxysteroid dehydrogenase in the kidney for the effects of N and T on these tissues. Following infusion of a combined dose of 3H-N and 3H-T there is a preferential retention at the receptor of 5 alpha-dihydrotestosterone (DHT) over 5 alpha-dihydronandrolone (DHN), N and T (DHT much greater than DHN greater than N greater than T) in the prostate because T is a better substrate than N for 5 alpha-reductase and because DHT binds more strongly to the androgen receptor than DHN, N and T.

Relative binding affinity of steroids for the corticosterone receptor system in rat hippocampus.

In cytosol of the hippocampus corticosterone displays highest affinity for the sites that remain available for binding in the presence of excess RU 26988, which is shown to be a "pure" glucocorticoid. A rather high affinity (greater than or equal to 25%) was found for 11 beta-hydroxyprogesterone, 21-hydroxyprogesterone, 5 alpha-corticosterone, 19-nor-deoxycorticosterone, 11-deoxycorticosterone and cortisol. A moderate affinity (greater than 5% and less than 25%) was displayed by about 14 steroids among which progesterone, aldosterone, 9 alpha-fluorocortisol and dexamethasone.