AN ENDOGENOUS PEPTIDE ISOLATED FROM THE GUT, NK-LYSIN, STIMULATES INSULIN-SECRETION WITHOUT CHANGES IN CYTOSOLIC-FREE CA2+ CONCENTRATION

We have recently isolated and cloned a novel endogenous peptide from p ig intestine, NK-lysin (NKL), In the present study we show that NKL (1 -100 nM) potently and reversibly stimulates insulin secretion in rat p ancreatic islets and in the beta-cell line HIT T15, This effect of NKL was not accompanied by changes in cytoplasmic free calcium concentrat ion. The stimulatory activity of NKL on insulin release was also obser ved in permeabilized islets under Ca2+-clamped conditions. Preincubati on of HIT T15 cells with NKL for 1 h or 24 h did not influence cell vi ability. Possible mechanisms of insulinotropic activity of NKL are dis cussed. (C) 1998 Federation of European Biochemical Societies.