ACTION OF NICOTINE ON THE PITUITARY-ADRENAL CORTICAL AXIS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 237  (1) , 49-66
Abstract
Nicotine raised dramatically plasma corticosterone levels in rats in a dose-dependent manner. Plasma corticosterone time course for the 100 .mu.g/kg dose of nicotine produced an initial increase in corticosterone elevation which did not return towards control levels until after 30 min. The 200 and 500 .mu.g/kg doses indicated a biphasic response for nicotine-induced steroid secretion. The 1st steroid peak occurred 1-5 min after nicotine administration and was followed by a greater elevation at 20 min. Plasma nicotine levels did not show the same biphasic pattern. The nicotine-induced plasma steroid elevation was completely abolished by hypophysectomy, indicating that the response to nicotine might be mediated through ACTH release from the anterior pituitary. The administration of exogenous ACTH to rats pretreated with betamethasone resulted in a biphasic plasma steroid elevation similar to that seen after injection of 200 .mu.g/kg nicotine. This may reflect a differential response of the adrenal cortex to a single ACTH outflow.