title: Methionine-enkephalin, leucine-enkephalin methionine-enkephalin-Arg6-Phe7 and methionine-enkephalin-Arg6-Gly7-Leu8 in human pheochromocytoma.
abstract: Methionine-enkephalin(met-enkephalin)-, leucine-enkephalin(leu-enkephalin)-, methionine-enkephalin-Arg6-Phe7(met-enkephalin-Arg-Phe)- and methionine-enkephalin-Arg6-Gly7-Leu8(met-enkephalin-Arg-Gly-Leu)-like immunoreactivities(-LI) were studied in 16 pheochromocytomas by radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Phe-LI and met-enkephalin-Arg-Gly-Leu-LI existed together with met-enkephalin-LI and leu-enkephalin-LI in 16 pheochromocytomas. Significant positive correlations were observed among contents of these four opioid peptides in 16 pheochromocytomas. The concentrations of these four opioid peptides in epinephrine producing pheochromocytomas were much higher than those in norepinephrine producing tumors. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe and met-enkephalin-Arg-Gly-Leu together with their high molecular weight forms. These results indicate the co-existence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe, met-enkephalin-Arg-Gly-Leu and their high molecular weight forms derived from preproenkephalin A in human pheochromocytomas and suggest the association of preproenkephalin A synthesis with epinephrine production in human pheochromocytomas.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000032:analysis*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004743:Enkephalin, Leucine / Q000302:isolation & purification*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000302:isolation & purification*; D006801:Humans; D010673:Pheochromocytoma / Q000032:analysis*; D011863:Radioimmunoassay
chemical_list: D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C027511:enkephalin-Met, Arg(6)-Phe(7)-; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-