Inhibition of Release of Corticotrophin

Abstract

MOST present concepts of the mechanism of stress activation of the adenohypophysis include the idea of neuro-endocrine ‘releasing factors’ which liberate a portion of the stored preformed corticotrophin¹. In contrast to the depletion of corticotrophin demonstrated by Rochefort et al.² during prolonged stresses, we have not been able to demonstrate any depletion after stress of short duration during the period of marked elevation of circulating corticotrophin. In adrenalectomized animals, there is actually an elevation of adenohypophyseal corticotrophin content coincident with the period of peak blood-level of corticotrophin³. This has led us to consider that, in the pituitary, stimulation of biosynthesis of corticotrophin is a very important element in the response to acute stresses. For this reason, we felt that it might be of interest to determine whether a blockade of corticotrophin biosynthesis would have any effect on the subsequent ability to release this hormone. We examined the effect of ethionine pre-treatment upon the stress-induced secretion of corticotrophin in rats.