Regulation of male fertility by pyrimethamine in adult mice.

Studies were carried out to determine the antifertility and reversibility effect of pyrimethamine (PYR) in adult male mice. The parameters mainly included sperm count and motility, fertility, histoarchitecture of testis and testicular cell kinetics quantitatively following oral administration of PYR (50 mg/kg body weight per day) for 30 days. The same parameters were also studied in PYR-treated animals which were allowed to recover for 45 days (recovery group). The results suggest that sperm motility as well as counts were significantly decreased in PYR-treated animals, and the fertility rate fell to zero. Testicular histology as well as germ cell kinetics were altered. However, in the animals of the recovery group, all the parameters studied were more or less similar to those of control animals. The study demonstrates the antifertility as well as reversible efficacy of PYR.