The antidiabetic effect of L-carnitine in rats: the role of nitric oxide system

Nowadays, the use of L-carnitine in the treatment of diabetes is increasing. This study was conducted to investigate the effect of co-administration of L-arginine (precursor for the synthesis of nitric oxide) and nitro-L-arginine (nitric oxide synthesis inhibitor) on antidiabetic activity of L-carnitine in diabetic rats.
In this study, 50 male rats weighing 180-201g were divided into five groups: (1) non diabetic control rats; (2) untreated diabetic rats; (3) diabetic rats treated with L-carnitine 300 mg/kg (4); diabetic rats treated with L-carnitine 300 mg/kg L-arginine 300 mg/kg; and (5) diabetic rats treated with L-carnitine (300 mg/kg) nitro-L-arginine (1mg/kg). Type 1 diabetes was induced by a single intraperitoneal injection of 110 mg/kg body weight alloxan. After 30 days, liver malondialdehyde levels, lipid profile, serum glucose, and glycated hemoglobin serum levels were measured.
Blood glucose, liver enzymes, glycated hemoglobin, and liver malondialdehyde levels significantly decreased in diabetic rats treated with L-carnitine compared to the untreated diabetic group (P The results suggest that the hypoglycemic effect of L-carnitine is mediated independently from nitric oxide pathways. The interaction between L-carnitine and L-arginine may not be synergistic. So, their combined administration is not recommended for the diabetic patients.