Abstract

The present paper is an evaluation of the studies of two articles published in this issue of the journal which adopted a new regimen of low dose gossypol(12 mg.kg-1.d-1) combined with steroid hormones (methyltestosterone 20 mg.kg-1.d-1 and ethinyl estradiol 100 micrograms.kg-1.d-1) for 6 weeks as initial dose, and a similar low dose gossypol alone for 12 weeks as maintenance dose. Results showed that the dosage regimen could damage the epididymal sperms and onset of antifertility within 6 weeks in male rats, and prevent the incidence of the side effect of irreversible azoospermia. There was no adverse effect in viscera tissues, and the infertility could be reversible in about 6 weeks following withdrawal of gossypol. Male volunteers taking low dose gossypol (15 mg/d) could induce antifertility within 12 weeks, then followed by a maintenance dose of gossypol(10 mg/d) for 44 weeks. All of them remained infertile, and without developing hypokalemia and irreversible azoospermia. The fertility and the inducing abnormal histone-to-protamine replacement reaction as well as alteration of nuclear basic proteins could be recovered 10 weeks after withdrawal of drug treatment. These results provide a new approach for using the new regimen in clinical trial and a new prospect of gossypol as a potential male contraceptive.