The Journal of nutrition
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The Journal of nutrition · Mar 2004
Dietary L-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats.
This study tested the hypothesis that dietary arginine supplementation increases endothelial tetrahydrobiopterin (BH(4)) availability for nitric oxide (NO) synthesis in diabetic rats. Streptozotocin-induced diabetic rats either were given unrestricted access to a casein-based diet (Expt. 1) or were pair-fed the diet on the basis of the food intake per kg of body weight of nondiabetic rats (Expt. 2). Beginning 1 d after vehicle or streptozotocin injection, arginine-HCl (1.51%) or alanine (isonitrogenous control, 2.55%) was added daily to the drinking water for nondiabetic rats, whereas concentrations were adjusted (0.43% arginine-HCl and 0.73% alanine) in the drinking water for diabetic rats (which consumed more water) to ensure isonitrogenous provision. ⋯ Dietary arginine supplementation or provision of a BH(4) precursor normalized endothelial NO synthesis in diabetic rats. Arginine supplementation did not affect plasma glucose levels in nondiabetic rats, but reduced body weight loss and plasma glucose levels in diabetic rats. Thus, dietary L-arginine supplementation stimulates endothelial NO synthesis by increasing BH(4) provision, which is beneficial for vascular function and glucose homeostasis in diabetic subjects.