Acquisition of conditioned avoidance responses by hypophysectomized rats.

Maintained hypophysectomized and sham-operated male Wistar rats on a complete high-carbohydrate dietary supplement in addition to ordinary diet to insure a state of good health. Groups so maintained were compared with respect to their ability to acquire the conditioned 2-way avoidance response 2, 3, and 5 wk. after operation. Sham-operated and hypophysectomized Ss both acquired the response with no significant differences. Almost all groups, however, included Ss which did not acquire the response. Hypophysectomized groups contained fewer of these Ss. Examination of a sample from a normal unoperated Wistar population without dietary supplement showed a proportion of Ss which did not acquire the response similar to that found with the sham-operated Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)