title: Catecholamines and opioid peptides in human phaeochromocytomas.
abstract: The tissue contents of catecholamines (CAs) and methionine-enkephalin-like immunoreactivity (Met-enk) were examined in 8 patients with phaeochromocytomas (Phs). In 6, Ph cells were cultured, and the modes of secretion of CAs and Met-enk were examined. Tissue contents of CAs and Met-enk varied from patient to patient, but larger amounts of Met-enk were found in medullary Phs than extramedullary ones, regardless of the secreting CA type. Three patients with extramedullary Phs had clinically showed a sustained hypertension, whereas five with medullary Phs were normotensive or had occasional paroxysmal hypertension. Nicotine (10(-7) M to 10(-4) M) stimulated simultaneous secretion of CAs and Met-enk from the cultured human Ph cells. Met-enk, however, was not secreted in proportion to either epinephrine (E), norepinephrine (NE) or total CAs (E + NE). Met-enk, FK33-824 (FK) (Met-enkephalin analogue), and dynorphin 1-13 (Dyn) significantly suppressed the secretion of CA evoked by 10(-5) M nicotine. The 50% inhibitory concentrations (IC50) of Met-enk, FK, and Dyn were 5 X 10(-6) M, 9.9 X 10(-5) M, and 9.0 X 10(-8) M, respectively, in one patient and 9.0 X 10(-6) M, 1.5 X 10(-7) M, and 1.4 X 10(-7) M in another. In one patient, 10(-5) M naloxone inhibited the CA secretion evoked by 10(-5) M nicotine and did not reverse the 10(-5) M FK-induced suppression of CA secretion in the presence of 10(-5) M nicotine. These results suggest that human Phs may be heterogeneous with regard to storage and secretion of CAs and opioid peptides.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000032:analysis*; D000328:Adult; D002478:Cells, Cultured; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin / Q000494:pharmacology; D004723:Endorphins / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000032:analysis*; D004837:Epinephrine / Q000032:analysis*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009270:Naloxone / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D009638:Norepinephrine / Q000032:analysis*; D010673:Pheochromocytoma / Q000032:analysis*
chemical_list: D004723:Endorphins; D009270:Naloxone; D004744:Enkephalin, Methionine; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D009538:Nicotine; D009638:Norepinephrine; D004837:Epinephrine