Methionine-enkephalin and leucine-enkephalin in human sympathoadrenal system and pheochromocytoma.
To elucidate the physiological and pathophysiological significance of methionine- and leucine-enkephalin (Met-and Leu-enkephalin, respectively) in human sympathoadrenal system, the contents of these peptides in normal human sympathetic nervous system, adrenal medulla, and pheochromocytomas were determined by specific radioimmunoassays combined with reverse-phase high-performance liquid chromatography. Met-enkephalin-LI and Leu-enkephalin-LI, respectively) were detected by radioimmunoassay in adrenal glands, adrenal medulla, stellate ganglia, sympathetic trunks, and celiac ganglia, and their contents in adrenal medulla were highest. Existence of authentic Met- and Leu-enkephalin was confirmed by reverse-phase high-performance liquid chromatography. Met-enkephalin was approximately 74% of Met-enkephalin-LI, whereas Leu-enkephalin was approximately 30% of Leu-enkephalin-LI in human adrenal medulla. The ratio of Met- to Leu-enkephalin was 2.6 in human adrenal medulla, whereas it was higher in sympathetic ganglia or trunks. In four cases of pheochromocytoma marked difference in Met- and Leu-enkephalin contents was found between medullary and extramedullary tumors. The contents were about three orders higher and the Met- to Leu-enkephalin ratio was lower in medullary than in extramedullary pheochromocytomas, reflecting the tissues where the tumors arose. These results suggest the physiological roles of Met- and Leu-enkephalin in sympathetic nervous system and adrenal glands and their pathophysiological significances in pheochromocytomas.
D000310:Adrenal Gland Neoplasms / Q000032:analysis*; D000313:Adrenal Medulla / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000502:physiology*; D004743:Enkephalin, Leucine; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000032:analysis / Q000502:physiology*; D006801:Humans; D010673:Pheochromocytoma / Q000032:analysis*; D011863:Radioimmunoassay; D013564:Sympathetic Nervous System / Q000032:analysis*
D004723:Endorphins; D004745:Enkephalins; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine