Orchidectomy sensitizes male rats to the action of diazepam on burying behavior latency: role of testosterone.

The anxiolytic-like effect of diazepam (0.0, 0.5, 1.0 mg/kg) on the cumulative burying behavior and the burying behavior latency were compared between intact and castrated male rats. In both groups a clear reduction in cumulative burying, denoting an anxiolytic-like response, was observed. However, castrated males were more sensitive to diazepam in the burying behavior latency, a parameter indicating reactivity. Thus, orchidectomized males showed an increase in burying behavior latency after 1.0 mg/kg diazepam treatment. This dose has no effect on burying behavior latency in intact animals. The higher sensitivity to diazepam on reactivity seems to be androgen dependent because it was reversed by chronic treatment with testosterone propionate (TP, 0.0625 mg/rat for 2 weeks). TP (0.0, 0.0625, 0.125, 0.25, 0.5 and 1.0 mg/rat) produced a dose-dependent reduction in burying behavior after chronic treatment (four injections separated 48 h). At no dose did TP affect burying behavior latency. These results indicate that some actions of diazepam vary in males depending upon the endocrine milieu. Results also support the idea of androgens possessing anxiolytic-like actions.