Melanotropin-potentiating factor isolated from filtrate of uremic patients suffering from melanosis and carbohydrate intolerance.

Following the characterization of a hexadecapeptide,α-endorphin, melanotropin-potentiating factor (MPF) was isolated from the filtrate of uremic patients suffering from melanosis and carbohydrate intolerance. The structure of MPF has been determined on the bases of chemical and physicochemical examinations which included HPLC, Edman sequence analysis combined analysis of the amino acid composition and FAB-MS analysis. An accumulation of MPF might be a cause of melanosis in uremic patients.