The Effects Of L-Arginine On Blood Pressure And Other Related Factors In Insulin-resistant Rats

ABSTRACTObjective: In the present study, we examined the effects of L-Arginine on Blood pressure and insulin-resiatance and correlations in fructose-fed-rats in order to discuss whether L-Arginine can prevent elevated blood pressure and improve insulin-resiatance and what about the underlying mechanism. Methods: After adaptively fed for one week, Male Sprague-Dawley(SD) rats aged 5-6 weeks were divided into four groups:Fructose-fed (FFR) given with 60% high fructose-diet, Control given with irregular diet; Fructose+L-Arginine fed (FFR+L-Arg) given with high fructose-diet and 2.25% L-arginine solution, L-Arginine- fed(L-Arg) given with irregular diet and 2.25% L-arginine solution. Blood pressure is measured weekly and plasm insulin and glucose is measured every one week. After all rats were sacrificed and their blood samples were collected, the concentrateion of fasting serum insulin(FINS), plasm endothlin(ET), plasm angiotension II( Ang-II), plasm tumbor necross factor-a (TNF ?a) were measured by Radical Immunology Assay(RIA). Serum glucose, nitric oxide(NO), triglyceride(TG), Superoxide Dismutase(SOD), Maleic Dialdehyde(MDA) were measured by biochemistry . Insulin-resisitance is e valued by insulin-acting Index (I AI)Results: 1. Fructose feeding resulted in hyperinsulinemia and evelated blood pressure and serum TG, (P<0.05). The number of Insulin Active Index(IAI) was evelated in contrast to the control (?<0.05). The body weight(BW) and glucose in all were equal, (P>.05).2. Serum NO was decreased and plasm ET or Ang-II was increased in FFR . (compared with control, P < 0.05) .3Abstract3. Serum SOD was decreased and serum MDA and TNF - a was increased in the FFR. (compared with control, P<0.05).4 . Blood-pressure, serum insulin and triglyceride were decreased in the FFR+L-Arg compared with FFR ( P<0.05) but were increased compared with the L-arg or the Control( P<0.05).5. Serum NO was increased and plasm ET was decreased in the FFR+L-Arg compared with FFR ( P<0.05). Those were equal compared with the L-Arg or the Control( P>0.05). plasm Ang-II was decreased compared with FFR ( P<0.05) but was increased compared with the L-Arg or the Control ( P<0.05). 6 serum TNF - a were decreased in the FFR+L-Arg compared with FFR ( P< 0.05) but were increased compared with the L-Arg or the Control( P<0.05). 7. Serum SOD was increased in the FFR+L-Arg compared with FFR ( P<0.05) and equal compared with the Control( />.05). serum MDA were decreased in the FFR+L-Arg compared with FFR ( P<0.05) but were increased compared with the L-Arg or the Control( /><0.05).Conclusion 1 . High- fructose-feeding can result in insulin resistance, evelated blood pressure and dyslipidemia with serum insulin evelated perceived by blood pressure. L-Arginine can prevent blood pressure evelated and improve insulin resistance and dyslipidemia. 2. High- fructose-feeding can result in endothelium dysfunction, decrease serum NO and increase plasm ET and Ang-II. L-arginine can improve endothelium function and decrease vessels-constractor. 3. High-fructose-feeding can result in oxide stresss, lower serum SOD and promote serum MDA. L-arginine can attenuate oxide stresss. 4. TNF- a is evelated in insulin resistance in Fructose-Fed Rats. L-Arginine can lower serum TNF- a.