PITUITARY-ADRENAL ACTIVATION IN RATS WITH MEDIAL BASAL HYPOTHALAMIC ISLANDS

Publisher Website
Google Scholar
Abstract
Male rats subjected to deafferentiation of the medial basal hypothalamus by the method of Halasz and Pupp were exposed to a variety of ACTH releasing stimuli during the forenoon. Following this, plasma corticosterone was measured and the results were compared with responses obtained in intact animals. The response to etherization alone was unaffected by deafferentation, although the plasma corticosterone increase due to etherization plus jugular venesection was slightly inhibited. There was, however, a nearly complete inhibition of the response to auditory stimulation (86% of control value) and also a marked inhibition of the response to optic stimulation (45% of control value). The responses to anoxia and immobilization were unaffected by the surgical procedure. The completeness of the hypothalamic »island« was not a factor of importance in these experiments since results were essentially the same in animals in which part of the tissue at the base of the hypothalamus was not cut. It is concluded that (1) ACTH release following auditory, and to a somewhat lesser extent, optic stimulation depends on neural input to the basal medial hypothalamus and (2) the corticotrophic responses to ether, anoxia and immobilization may be mediated by humoral activation of the same region.

This publication has 0 references indexed in Scilit: