Plasma beta-endorphin responses to somatostatin, thyrotropin-releasing hormone, or vasopressin in Nelson's syndrome.

To elucidate the regulation of secretion of beta-endorphin in Nelson's syndrome, both ACTH and beta-endorphin were measured using RIA. We found that beta-endorphin and ACTH were secreted concomitantly in responses to the administration of lysine-8-vasopressin and TRH. Conversely, the administration of somatostatin to this patient reduced the secretion of both beta-endorphin and ACTH. Thus, beta-endorphin is probably secreted cooredinately with ACTH in patients with Nelson's syndrome.