Treatment of oligozoospermia by tamoxifen: no evidence for direct testicular action.

The improvement of impaired spermatogenesis by tamoxifen is well documented. The antiestrogen seems to act via an enhancement of gonadotropin release from the hypophysis, but there is evidence for a direct testicular effect. Thus we studied the serum levels of gonadotropins and steroid hormones in 22 patients with idiopathic oligozoospermia. To study the direct testicular effect, we tested the response of 5 normal males to hCG prior to and after the application of tamoxifen. FSH levels showed a continuous increase in the patients during the three months of treatment, while the stimulation by LH-RH was not altered. In the case of LH the basal as well the stimulated levels increased. Mean levels of testosterone, 17-hydroxyprogesterone, androstenedione and estradiol increased significantly during treatment. Sperm counts of patients were found to be considerably higher after three months. In the normal males no differences in steroid levels as a response to hCG with and without tamoxifen treatment occurred. Our results give evidence, that the hormonal changes occurring under tamoxifen treatment are not due to a direct testicular effect.