[The effect of hormones from the peripheral endocrine glands on behavioral, learning and memory processes]

The present study was designed to explore the comparative influence of thyroid, adrenal, and gonadal hormones on the capability for learning, retention of memory traces and behavior in male rats under conditions of systemic administration of synthetic hormonal preparations. Behavior of animals was assessed during the active and passive avoidance learning, as well as in the open-field test. It was established that the increase in the level of corticosteroid, thyroid, or gonadal hormones did not affect the formation and retention of passive avoidance learning. Excess of corticosteroids increased behavioral activity but impaired the active avoidance learning and the following reproduction of the acquired reaction. Excess of gonadal hormones dramatically impaired the performance in the conditioned active avoidance test, and excess of thyroid hormones improved the active avoidance learning.