Neonatal androgen levels and avoidance learning in prepubescent and adult male rats

Neonatal male rats were injected with 1.25 mg of testosterone propionate (TP) and compared with oil-injected controls on the acquisition of an active and passive avoidance response at 25 days of age. The TP treated animals acquired the active avoidance response significantly faster than controls, but no differences were found between groups tested on the step-down passive avoidance task. The active-avoidance paradigm was repeated at 70 days of age, with experimental and control animals receiving the same neonatal treatment as the prepubescent subjects. Again the TP group showed facilitated acquisition of the active avoidance response. The TP treatment also produced an increase in activity levels and aversion threshold to footshock in the prepubescent animals. Therefore the active avoidance effect may be interpreted more parsimoniously as a reflection of these latter effects, rather than learning per se.