Pituitary adenomas that caused Cushing's disease or Nelson's syndrome are not responsive to ovine corticotropin-releasing factor in vitro.
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.
D000236:Adenoma / Q000150:complications / Q000503:physiopathology*; D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000328:Adult; D002478:Cells, Cultured; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D003480:Cushing Syndrome / Q000209:etiology*; D003907:Dexamethasone / Q000494:pharmacology; D004723:Endorphins / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism; D009347:Nelson Syndrome / Q000209:etiology*; D010911:Pituitary Neoplasms / Q000150:complications / Q000209:etiology* / Q000503:physiopathology*; D013004:Somatostatin / Q000494:pharmacology; D053561:Somatostatin-28; D014667:Vasopressins / Q000494:pharmacology; D001615:beta-Endorphin
D004723:Endorphins; D014667:Vasopressins; D013004:Somatostatin; D001615:beta-Endorphin; D053561:Somatostatin-28; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D003346:Corticotropin-Releasing Hormone