Protective effect of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) synthetase, against streptozotocin-induced diabetes.

The addition of 3-aminobenzamide (a potent inhibitor of poly(ADP-ribose)synthetase) into the incubation medium, prevents streptozotocin-induced inhibition of glucose-stimulated insulin release from isolated islets [control 142 +/- 14 microU X islet-1 X h-1; streptozotocin (0.5 mg/ml) 31 +/- 8; 3-aminobenzamide (1.0 mg/ml) 96 +/- 11; streptozotocin plus 3-aminobenzamide 122 +/- 19]. In vivo, intraperitoneal 3-aminobenzamide 300 mg/kg body weight prevents the appearance of overt diabetes in streptozotocin-treated rats. These protective effects of 3-aminobenzamide are dose-dependent and are similar to those exerted by nicotinamide. Taking into account that poly ADP-ribosylation is involved in the repair of damaged DNA, the protection exerted by 3-aminobenzamide against the diabetogenic effect of streptozotocin strongly supports the view that this acute effect may be a major consequence of the activation of DNA repair mechanisms in islet cells.