New horizons in contraception

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.

Pyrimethamine: an approach to the development of a male contraceptive

With the human population of the world currently more than 5.2 billion and growing at an explosive rate, the need for additional forms of readily available contraception appears paramount. To date, contraception techniques in the male have been very limited. The present study demonstrates the ability of pyrimethamine (PYR) to cause spermatogenic arrest and male infertility in mice in a dose-dependent manner. Furthermore, upon cessation of drug administration all animals returned to normal fertility status. It is also suggested that the action of PYR is due to its antifolate action. Thus, PYR represents another approach toward development of a male contraceptive.