Biological activity of some steroidal compounds in the adult and larval frogs

Four steroids were tested for their biological activity, using the sex-steroid-dependent redevelopment of the secondary sex characteristics in adult frogs and gonadal sex differentiation in larval frogs as end points. In adult frogs, 19-norprogesterone and 6-chloro-17alpha-hydroxy-4, 6-pregnadiene-3,20-dione had antiandrogenic and antiestrogenic effects. 2alpha, 17alpha-Dimethyl-DHT and 2alpha-methyl-DHT were potent androgens and effective antiestrogens. In the larval frogs, all four compounds had a masculinizing effect upon the undifferentiated gonads.