1,4dihydro 2,6dimethyl 4 4.nitrophenyl)  , 5pyridinedicarboxylic acid dimethyl ester (DDNPD), is a new analogus of nifedipine that has no effect on calcium channels of cardiovascular system. Because nifedipine can reduce fertility in males( through effect on calcium channels on sperm membrane and inhibition of acrosomal reaction), this study was done to  evaluate the effect of DDNPD on reproductive system physiology and fertility in male rats.

          In this research, DDNPD was injected 10mg/kg twice a day subcutaneously to the test group of adult male rats for 50 days. Control group treated with propylene glycol 1mg/kg twice a day in the same way.

          In the assessment of some fertility indices , we saw a significant decrease in motility and viability rate of sperm (P<0.001), the epididymal sperm reserve rate (P<0.001) and fertility rate (P<0.001) in the test group but there was no difference in testosterone level between the groups.

          These results are conclusive of posttesticular antifertility effect of DDNPD if injected 10mg/kg for 50 days to male adult rats.