Dynamic study of serum gonadotrophin and testosterone levels in gossypol‐treated men Long term follow‐up study of 60 cases

This study investigated the endocrine effects of gossypol in 26 men over a 52-month period before during and after treatment and in an additional 34 men after cessation of treatment. A control group of 60 age-matched volunteers was monitored for 1 year. The treatment dose in the 1st group of subjects was 20 mg/day for 60-75 days followed by a maintenance dose of 50 mg/week. No significant changes in testosterone levels were observed between cases and controls. However serum luteinizing hormone (LH) levels were significantly higher during early phases of gossypol treatment; these levels returned to normal after cessation of treatment in all but 14 men who experienced persistent disruption of spermatogenesis. Serum levels of LH and testosterone were significantly higher in these 14 men than in normal persons and significantly lower than those in subjects in whom spermatogenesis had recovered. Although azoospermia generally occurred within 76 days after treatment onset serum follicle stimulating hormone (FSH) levels did not rise during the first 8-9 months of treatment. After 9 months of treatment however FSH levels rose gradually and remained significantly elevated after treatment cessation in both the azoospermic/oligospermic group and in the group in which spermatogenesis was recovered. In the latter group serum FSH levels were significantly associated with the sperm concentration. The longterm follow-up data suggest that Leydig cell function is affected by gossypol treatment and higher levels of LH are required to maintain normal testosterone levels leading to compensated Leydig cell failure. It is proposed that the risk of irreversible azoospermia and other side effects could be minimized if the dosage and duration of gossypol treatment were monitored using parameters other than the onset of azoospermia. A review of the utility of testicular cell damage indicators is needed before gossypol can achieve its potential as a male contraceptive.