pituitrin and Nelson-Syndrome

The response of pituitary adenomas obtained surgically from patients with Cushing's disease of Nelson's syndrome to synthetic ovine corticotropin-releasing factor (CRF), vasopressins, somatostatin-28, dexamethasone, 3-isobutylmethylxanthine or high [K+] was examined in vitro by measuring the amount of pro-opiomelanocortin (POMC)-derived peptides secreted into the culture medium. CRF did not stimulate the secretion of adrenocorticotropin-, beta-endorphin-, or gamma 3-melanotropin-like peptides from the pituitary adenomas at concentrations ranging from 1 x 10(-13) M to 1 x 10(-7) M whereas vasopressins, 3-isobutyrl-methylxanthine and high [K+] increased, while somatostatin-28 and dexamethasone suppressed, the secretion of these POMC-derived peptides. These findings suggest that either the pituitary ACTH-producing tumors have lost their receptors to CRF or their post-receptor mechanism to CRF is not functional.

Topics: Adenoma; Adolescent; Adrenocorticotropic Hormone; Adult; beta-Endorphin; Cells, Cultured; Corticotropin-Releasing Hormone; Cushing Syndrome; Dexamethasone; Endorphins; Female; Humans; Male; Melanocyte-Stimulating Hormones; Nelson Syndrome; Pituitary Neoplasms; Somatostatin; Somatostatin-28; Vasopressins