Abstract

L-ARGININE PREVENTS ENDOTHELIAL DYSFUNCTION AND RESTORES TETRAHYDROBIOPTERIN LEVEL IN EXPERIMENTAL DIABETES

Ehsan Badawy, Dina Abo El-Matty, Hanaa Wafaay, Hoda Megahed, Omnia Aly and Jihan Hussein*

ABSTRACT

L-arginine is the precursor of nitric oxide (NO), the most important factor responsible for diabetes associated cardiovascular complications. In this study, we explored whether L-argenine supplementation is able to stabilize tetrahydrobiopterin (BH4) during experimental diabetes, and we also investigated how critical the elevation of BH4 and total biopterin in affecting the endothelial dysfunction. Seventy five male albino rats weighting 180-200 g were divided into five groups; control, L-arginine, diabetic, treated and prophylactic groups. After the experimental period, fasting blood samples were collected from all groups for determination of fasting blood glucose, insulin and NO. Total biopterin, and BH4 were determined by HPLC; separation was achieved on reversed phase column (250 mm x 5 μm). Column temperature was 50 °C, the excitation and emission wavelengths were 360 and 440 nm respectively. The results showed a reduction in total biopterin, and BH4 in diabetic group, although, L-arginine significantly attenuated this reduction. In conclusion, oral administration of L-arginine markedly increased BH4 availability and NO. L-Arginine may be a novel nutrient, which has important implications for the prevention and treatment of diabetes mellitus.

Keywords: biopterin, tetrahydrobiopterin, endothelial dysfunction, L-arginine, HPLC.