Effects of pyridoxine on male fertility.

Pyridoxine (PN) was intraperitoneally given at 250 and 500 mg/kg to male rats for 2, 4, or 6 weeks, and its effects on male fertility evaluated in terms of the optimal treatment period and detection parameters. Animals of all PN groups showed depression of body weight gains from week I of treatment onwards, significant at all but the 250 mg/kg 2 week administration I week time point. After 2 weeks treatment, the testes demonstrated only very slight histopathological changes. The 4- and 6-week treatments caused decreased spermatozoal motility and some histopathological changes in the testes including degeneration of germinal epithelial cells with both doses and also decreases in the fertility index and mean velocity of sperm, reduction in the testes and epididymides weights, and changes in testicular proteins. In the animals undergoing a 4-week recovery period following 4 or 6 weeks exposure, changes disappeared with the 250 mg/kg dose, but still remained with 500 mg/kg. From these findings, it is concluded that a treatment period of 4 weeks is sufficient for evaluation of drug effects on male fertility and that histopathology can detect the slightest toxic effects on the testis.