Preproenkephalin A-derived opioid peptides and mRNA of preproenkephalin A in human pheochromocytomas.
Tissue contents of immunoreactive met-enkephalin (Met-Enk), leu-enkephalin (Leu-Enk) and met-enkephalin-Arg-Gly-Leu (Met-Enk-AGL) were determined by specific RIAs in 17 pheochromocytomas and the levels of preproenkephalin A mRNA were compared in some of these tissues by Northern blot hybridization. Remarkably wide distributions in the amounts of immunoreactive Met-Enk, Leu-Enk and Met-Enk-AGL were observed in 17 pheochromocytomas. Medullary pheochromocytomas contained significantly larger amounts of immunoreactive Met-Enk, Leu-Enk and Met-Enk-AGL than did the extramedullary ones. Significant positive correlations of tumor tissue immunoreactivities between Met-Enk and Leu-Enk (r = 0.97, P less than 0.01) and between Met-Enk and Met-Enk-AGL (r = 0.97, P less than 0.01) were observed. No difference in size of mRNA of preproenkephalin A was observed in the pheochromocytomas. Medullary pheochromocytomas contained higher amounts of preproenkephalin A mRA than did the extramedullary ones. The quantities of preproenkephalin A mRNA in nine pheochromocytoma tissues significantly correlated with those of immunoreactive Met-Enk in these tissues (r = 0.94, P less than 0.01). These results indicate that the remarkable difference in tissue immunoreactivities of preproenkephalin A-derived opioid peptides is decided at the transcriptional level but not at the posttranslational level.
D000310:Adrenal Gland Neoplasms / Q000032:analysis*; D000328:Adult; D004743:Enkephalin, Leucine / Q000032:analysis; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000032:analysis; D004745:Enkephalins / Q000032:analysis* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D010673:Pheochromocytoma / Q000032:analysis*; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D011863:Radioimmunoassay
D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-; C033660:preproenkephalin