| Abstract: | The in vitro inhibitory activity of five new progesterone derivatives: 17alpha-hydroxy-16beta-methylpregna-1,4,6-triene-3,20-dione 1; 16beta-methyl-17alpha-toluoyloxypregna-1,4,6-triene-3,20-dione 2; 17alpha-hydroxy-6-methylenepregn-4-ene-3,20-dione 3; 6-methylene-17alpha-toluoyloxypregn-4ene-3,20-dione 4 and 17alpha-(p-bromobenzoyloxy)-6-methylenepregn-4-ene-3,20-dione 5 was determined. These compounds were evaluated as 5alpha-reductase inhibitors as well as antagonists for the androgen receptor. Compounds 1, 2, 3, 4 and 5 showed the following inhibitory activity for the 5alpha-reductase enzyme with IC(50) values of: 1 (1.65 microM), 2 (10 microM), 3 (19 nM), 4 (100 nM) and 5 (100 nM). The results of this study also showed the effect of increasing concentrations of the novel steroids upon (3)H]dihydrotestosterone binding to androgen receptors from male hamster prostate. The K(i) values for compounds 1, 2, 3, 4, 5 and dihydrotestosterone showed the following order of affinity for the androgen receptor: 4>5>dihydrotestosterone>2>3>1. The overall data indicated that all synthesized compounds 1, 2, 3, 4 and 5 are inhibitors of the 5alpha-reductase enzyme present in the hamster prostate. In addition compounds 1, 2, 3, 4 and 5 also presented an affinity for the androgen receptor. |
