NITRIC-OXIDE TOXICITY IN ISLET CELLS INVOLVES POLY(ADP-RIBOSE) POLYMERASE ACTIVATION AND CONCOMITANT NAD+ DEPLETION

Previous studies have shown that DNA strand breaks are an early conseq uence of nitric oxide toxicity in pancreatic islet cells. We show here that exposure of islet cells to chemical NO donors causes the formati on of ADP-ribose polymers in cell nuclei, with concomitant depletion o f intracellular NAD+. Islet cell lysis was largely prevented by the AD P-ribosylation inhibitors nicotinamide, 3-aminobenzamide, and 4-amino- 1,8-naphthalimide, the latter being a potent new-generation compound w ith high selectivity for poly(ADP-ribosyl)ation. These findings indica te a key role of poly(ADP-ribose) polymerase activation in NO toxicity in islet cells. (C) 1994 Academic Press, Inc.