Biotransformation of androst-4-ene-3, 17-dione (1), 3β-hydroxypregnan-5-en-20-one (pregnenolone, 2), 3β-hydroxyandrost-5-en-17-one (DHEA, 3) and estradiol (4) was investigated with fungus of Gelasinospora retispora. Biotransformation of 1 gave 11α- hydroxyandrost-4-ene-3, 17-dione (5) in good yield. In the case of compound 2, three compounds, DHEA (3), 3β, 17β-dihydroxyandrost-5-ene (6) and 3β, 15β-dihydroxyandrost ...