Poly(ADP-ribose) synthesis induced by nitric oxide in a mouse beta-cell line.

Nitric oxide (NO) has been implicated as an immunological effector molecule that mediates beta-cell dysfunction associated with Type 1 diabetes. To assess whether NO induces poly(ADP-ribose) synthesis in islet cells, we examined the effect of nitroprusside on islet cells. The exposure of mouse islet cells and a beta-cell line (beta TC1) to 0.05-0.2 mM nitroprusside resulted in the reduction of intracellular nicotinamide adenine dinucleotide (NAD) levels. Nitroprusside stimulated poly(ADP-ribose) synthetase activity in beta TC1 cells. An inhibitor of poly(ADP-ribose) synthetase, 3-aminobenzamide, prevented both NAD decrease and poly ADP-ribosylation. These observations suggest that NO-induced pancreatic beta-cell damage may be ascribable to the activation of poly(ADP-ribose) synthetase that results in the decrease of NAD content.