Regulation of hyperglycemia and dyslipidemia by exogenous L-arginine in diabetic rats

The effect of L-arginine on the pattern of lipids and lipoproteins in norma l and diabetic rats was studied. Three groups of 48 rats were studied durin g 12 days and compared with a control group (Group I, n = 5). Group I consi sted of normal rats not treated with L-arginine. Group II. Normal rats trea ted with 10 mM L-arginine (i.p.). Group III. Diabetic rats (alloxan 120 mg/ kg, i.p.) not treated (diabetic control), Group TV. Diabetic rats treated w ith 10 mM L-arginine (i.p.). The rats of each group were divided in subgrou ps of four each. Rats were anesthetized and blood was taken from aorta to d etermine glucose, triglycerides, cholesterol, total lipids, and low (LDL) a nd high density lipoproteins (HDL) and their corresponding apoproteins (Apo A-I and Apo B-100). We observed that the alloxan concentration used in thi s study reproduces the clinical manifestations of disease including hypergl ycemia (from 132.5 +/- 7.6 to 544.3 +/- 16.9 mg/dL) in 96 h, ns a consequen ce the levels of triglycerides, cholesterol, total lipids, and LDL and its apoprotein Apo B-100 were increased, whereas HDL and its apoprotein Apo A-T were diminished. The L-arginine injection tends to normalize the glycemia from 24 h; similarly, hyperlipidemia (triglycerides from 924.7 +/- 220.1 to 68.5 +/- 8.4 mg/dL, cholesterol from 107.7 +/- 0.6 to 64.5 +/- 4.2 mg/dL, LDL from 24.2 +/- 2.5 to 8.0 +/- 2.9 mg/dL) was also diminished. These resu lts suggest that the beneficial effect of L-arginine administration on seru m glucose values and lipid levels in diabetic rats can be mediated by polya mine formation, although the effect of L-arginine on insulin release as obs erved by other authors is not discarded. (C) 2001 societe francaise de bioc himie et biologic moleculaire/Editions scientifiques et medicales Elsevier SAS. All rights reserved.