Copulation in noncopulators: effect of PCPA in male rats

Twenty eight virgin male rats who failed to mount spontaneously on four successive mating tests were randomly assigned to two equal groups. One group received four daily injections of PCPA (100 mg/kg-IP), and the other, four vehicle injections. About 24 hr after the last injection all rats were subjected to a mating test. Eight rats of the PCPA group and only two of the vehicle, started to copulate. The difference is significant at the 0.05 level (two-tail). The 18 rats that did not start to copulate, failed to do so also on a repeated test a week later, and were then given four additional daily injections of PCPA. Sixteen of them started to copulate on the following mating test. Most of the rats copulated successfully on additional mating tests that took place three to eight weeks later, in the absence of further PCPA treatment.