Dissociation of the acute secretions of thyrotropin and adrenocorticotropin

Abstract

Plasma TSH [thyrotropin] and corticosterone concentrations were measured simultaneously in normal rats and animals pretreated with dexamethasone-pentobarbital, following mild acute stress procedures and acute exposure to cold. In both normal and dexamethasone treated animals, stress leads to inhibition of TSH secretion, not necessarily associated with an increased ACTH secretion. Cold exposure increases TSH secretion in both types of animal preparations; quantitatively however, more TSH is released in response to cold in animals with ACTH secretion blocked. It is concluded that the inhibition of TSH secretion in response to stress is a coincidence rather than a consequence of ACTH release, and the increased secretion of TSH due to cold exposure is inversely related to the concomitant secretion of ACTH.