Effects of drugs and chemicals on spermatogenesis

Many drugs and chemicals have been found which interfere with the process of spermatogenesis. Among these substances are, for example, sex-hormones (androgens, antiandrogens, estrogens, progestogens, anabolics), chemotherapeutics, antibiotics, antifungal drugs, anticancer drugs, nonsteroidal antiinflammatory drugs, antihypertensives, neuroleptics, dopaminantagonists, indols, tranquilizers, tricyclic antidepressives, heavy metals (Co, Cd), MAO-inhibitors, antimetabolites, barbiturates, immunosuppressives (glucocorticoids), aldosteronantagonists, anticonvulsives, and perhaps alcohol and nicotine. Concerning the mechanism by which spermatogenesis is effected several points of interference have to be considered: inhibition of gonadotrophin secretion, inhibition of enzymes involved in androgen biosynthesis, direct effects on the germinal epithelium or on Sertoli cell function, competitive inhibition of hormone action, damage of the blood-testes barrier and other mechanisms. Some of these mechanisms will be discussed.