A met-enkephalin analog inhibits adrenocorticotropin secretion by cultured pituitary cells from a patient with Nelson's syndrome.
ACTH excretion by cultured nonenzymatically dispersed pituitary tumor cells from a patient with Nelson's syndrome was studied. Hormone release was suppressed by 74 +/- 6% by the addition of 1 microM of the met-enkephalin analog FK 33824, while naloxone (1 microM) stimulated ACTH release by 70 +/- 5%. Somatostatin, dexamethasone, bromocriptine, and cyproheptadine in a concentration of 1 microM each inhibited ACTH release by 25 +/- 2%, 35 +/- 2%, 52 +/- 2%, and 61 +/- 4%, respectively, while lysine vasopressin (0.1 microM) and dibutyryl cAMP (5 mM) stimulated ACTH release by 112 +/- 8% and 220 +/- 4%, respectively. In conclusion, it was shown that the stimuli mentioned above directly affect ACTH secretion by the pituitary tumor cells. The inhibitory action of the met-enkephalin analog and the stimulatory action of naloxone on ACTH secretion make the presence of opiate receptors on this type of tumor likely.
D000236:Adenoma / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000328:Adult; D002478:Cells, Cultured; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology*; D005260:Female; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D009270:Naloxone / Q000494:pharmacology; D009347:Nelson Syndrome / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism*
D004723:Endorphins; D004745:Enkephalins; D006728:Hormones; D009270:Naloxone; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D000324:Adrenocorticotropic Hormone