Inhibits spermatogenesis without affecting production of gonadotropins in male laboratory animals. Prepn and biological activity: Surrey, Mayer, J. Med. Pharm. Chem. 3, 419 (1961); Surrey, US 3143566 (1964 to Sterling Drug). Assessment of antifertility activity in rats: S. Nag, J. J. Ghosh, J. Steroid Biochem. 11(1B), 681 (1979). Teratological study: P. Taleporos et al., Teratology 18, 5 (1978). Toxicology study: F. Coulston et al., Toxicol. Appl. Pharmacol. 2, 715 (1960).