Effect of poly(ADP-ribose) synthetase inhibitor administration to streptozotocin-induced diabetic rats on insulin and glucagon contents in their pancreas.
This study was conducted in order to clarify whether the poly(ADP-ribose) synthetase inhibitors, nicotinamide and 3-aminobenzamide, have any influence upon the content and physicochemical properties of insulin and glucagon in streptozotocin (STZ)-treated rat pancreas. STZ-treated rats received intraperitoneal injection of 350 mg/kg nicotinamide or 50 mg/kg 3-aminobenzamide 15 min before and 180 min after the administration of STZ and once a day thereafter for 23 weeks. The blood glucose levels and body weight of nicotinamide- and 3-aminobenzamide-treated rats did not differ from those of the control rats at the end of the experiment. The insulin content in poly(ADP-ribose) synthetase inhibitor-treated rat pancreas was restored partially and reached approximately 60% of the control level, while the glucagon content did not differ from that in the normal rats. Treatment with poly(ADP-ribose) synthetase inhibitor resulted in no alteration in the physicochemical properties of extracted insulin and glucagon. Immunohistological examination of the pancreas revealed that insulin- and glucagon-containing cells in the islets in the poly(ADP-ribose) synthetase inhibitor-treated rat appeared to be normalized. These results suggest that poly(ADP-ribose) synthetase inhibitor normalizes the function but not the insulin content of B cells and that it does not act on A cells in STZ-treated rat pancreas. Restoration of the insulin content would be large enough to keep the function of B cells normal.
D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005934:Glucagon / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D008297:Male; D009536:Niacinamide / Q000494:pharmacology; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D051381:Rats; D011919:Rats, Inbred Strains
D001549:Benzamides; D007328:Insulin; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D009536:Niacinamide; C025160:3-aminobenzamide; D005934:Glucagon