Studies on adrenorphin in pheochromocytoma.
We studied the secretion and tissue contents of adrenorphin in human pheochromocytomas. In 17 human pheochromocytomas from 11 patients, we found a remarkably wide distribution in immunoreactive adrenorphin levels (3-7771 pg/mg tissue). Adrenomedullary pheochromocytomas contained a significantly larger amount of immunoreactive adrenorphin (2295 +/- 1092 pg/mg, mean +/- SE) than did extramedullary ones (17.8 +/- 8.4 pg/mg). Gel chromatographic studies revealed that immunoreactive adrenorphin consisted largely of material emerging at the position of synthetic adrenorphin in both pheochromocytoma and normal adrenal medulla tissue. Nicotine (10(-5) M) significantly stimulated the secretion of immunoreactive adrenorphin as well as catecholamines from cultured human pheochromocytoma cells. Adrenorphin was a more potent inhibitor of catecholamine secretion evoked by 10(-5) M nicotine than was met-enkephalin in cultured human pheochromocytoma cells. The 50% inhibitory concentrations (IC50) were 1.1 X 10(-6) and 6.5 X 10(-5) M for adrenorphin and met-enkephalin, respectively. The effect of adrenorphin was much the same as that of dynorphin-(1-13) (IC50, 1.0 X 10(-6) M) and BAM-12P (IC50, 4.5 X 10(-6) M). These results indicate the presence and secretion of adrenorphin in human pheochromocytomas. Adrenorphin may play an important role in regulating catecholamine secretion in human pheochromocytoma.
D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000378:metabolism*; D000328:Adult; D002395:Catecholamines / Q000378:metabolism*; D004723:Endorphins / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology; D010673:Pheochromocytoma / Q000378:metabolism*
D002395:Catecholamines; D004723:Endorphins; D004744:Enkephalin, Methionine; D009538:Nicotine; C039700:adrenorphin; D005934:Glucagon