... and insulin-like growth factor I 13. 6.2 SYNTHETIC HGPS The structures of TBA (17 -acetoxyestra-4,9,11-triene-3-one), MGA (17 -acetoxy6-methyl-16-methylene-pregna-4,6-diene-3,20-dione), and zeranol ... 11 -hydroxy-4-androstene-3,17-dione and 11 -hydroxy-1,4-androstadiene-3,17-dione.111 The side-chain progesterone was degraded by some species of Aspergillus flavus; 4-androstene-3,17-dione, testosterone, ... 302 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 13. 4 NATURAL ANDROGENS Natural androgens are C-19 steroids that possess androgenic activities (stimulating and maintaining...