Antispermatogenic effects of tolnidamine in langur (Presbytis entellus).

Tolnidamine (50 mg/kg body weight; twice a week; oral) was administered for 90 days to adult male langur monkeys (Presbytis entellus entellus Dufresne) to assess its contraceptive potential. Semen weight, volume, seminal fluid volume, colour, pH and libido remained unchanged. Sperm motility, vitality and morphology were impaired with the advancement of treatment. Sperm density reduced to severe oligospermia following 75-90 days of treatment. Increased number of immature germ cells were also noticed. Resumption of changes to pretreatment range was observed following 90 days of cessation of treatment. However, sperm density remained low all through the recovery period of 150 days. Seminal fructose, ACP, LDH and citric acid concentrations did not change markedly. A significant depletion in GPC and magnesium levels was recorded during treatment and early recovery periods. Alterations in germ cells and Sertoli cells were also observed. A progressive but reversible rise in serum creatinine was evident. Other clinical parameters and body weight response revealed no drug-related alterations. In conclusion, tolnidamine medication induced irreversible inhibition of spermatogenesis.