Inhibition by somatostatin of ACTH secretion in Nelson's syndrome.

Somatostatin (GHIF), when administered as a 1-hr infusion (500 mug/hr) to 5 patients with Nelson's Syndrome;resulted in a sustained, progressive fall in plasma ACTH in each patient to 40% to 71% of basal values with a return toward initail levels after cessation of the infusion. The meanreduction in plasma ADTH was 48% (p less than 0.005). These finding suggest that GHIF receptors not fuctional or present in normal pituitary tissue are present in ACTH-producing pituitary tumors.