Chemical sterilization: effects of danazol administration on the testes and epididymides of male rabbit.

1. Danazol, a synthetic (2,3-isoxazole) derivative of 17 alpha-ethinyl testosterone has been studied in rabbits to support our earlier findings in dog, whether Danazol can be developed as an effective means for male contraception. 2. Chronic administration of Danazol resulted in a mass atrophy of the spermatogenic elements. Seminiferous tubule and Leydig cell nuclear dimensions were reduced. The lumen of epididymides and vas deferens were devoid of spermatozoa. These effects were reversible following a period of 60 days of recovery. 3. Hepatic function was followed with determination of SGOT, SGPT, alkaline phosphatase, cholesterol and blood sugar. Serum-amino-transferases were elevated during the period of administration but returned to normal after cessation of drug administration. 4. In conclusion, Danazol can be used as an effective means for male contraception in rabbit. The effects are reversible. Normal spermatogenesis occurs following a period of sixty days of recovery.