Nicotinamide Ameliorates Serum C-Peptide and Brain Tryptophan Levels in STZ-Induced Diabetic Sprague- Dawley Rats

Metabolic complications of Type-1 diabetes mellitus are a significant source of morbidity and mortality. Nicotinamide treatment has been reported to reverse pancreatic beta cell damage and used to prevent Type-1 diabetes mellitus. The effects of nicotinamide on fasting blood glucose, serum C-peptide and brain tryptophan have not been fully investigated. The objective of the study is to evaluate the effect of nicotinamide on fasting blood glucose, serum C-peptide and brain tryptophan levels in Streptozotocin (STZ) -induced diabetic rats. Type-1 diabetes was induced by intra-peritoneal injection of streptozotocin (55mg/kg) using Sprague-Dawley rats. After 2 days, the rats were divided into diabetic control and nicotinamide-treatment group. Nicotinamide was orally administered at daily doses of 375mg/kg and 500mg/kg for a period of 4 weeks, while another group of rats without this treatment served as control. The diabetic control group showed significant (p less than 0.05) increase in fasting blood glucose, but a decrease in serum CPeptide and brain tryptophan levels compared with the control. Treatments with 375mg/kg and 500mg/kg nicotinamide showed a significant decrease in fasting blood glucose, but an increase in serum C-peptide and brain tryptophan levels compared with diabetic control. Data of the study indicate that nicotinamide may prevent diabetic complications by alleviating its metabolic symptoms of hyperglycemia and polyphagia, which may ameliorates pancreatic islet cell damage in diabetic rats.