The contraceptive effect of gossypol in man has been studied for 30 years. Numerous studies revealed that gossypol was highly efficient in suppressing spermatogenesis, and it was used as a male contraceptive at the dose of 30mg/kg/d. However there were two side effects that were considered undesirable and affected around 10% of Chinese users. The first was a reduction of potassium (hypokalemia) level in blood; the other side effect was the irreversibility of its contraceptive effect. Studies conducted in our department recently showed that low dose (10-12.5mg/kg/d) gossypol could induce infertility, but the onset of contraception was largely delayed.The study of the role of steroid hormones in spermatogenesis has attracted significant interest in recent years, because of the increasing awareness that these hormones are essential for spermatogenesis in the male animal, and several steroid hormone male contraceptives has been developed on this basis. However, a hormonal contraceptive for men is likely to have some features and limitations. Firstly, it has a relatively slow onset and termination of action, usually 2-3months. This feature may probably remain for all male hormonal regimens and is similar to the time needed for the achievement of azoospernia after vasectomy. Secondly, it does not suppress spermatogenesis uniformly to azoospermia in all men.Through many years investigation, substantial progress in combining gossypol and steroid hormones together as a male contraceptive has been made, in our...
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