OBJECTIVE It has been shown that aspartate and glutamate inhibit mononuclear cell adhesion to the endothelium and formation of foam cells in the intima of thoracic aorta in cholesterol-fed rabbits. The purpose of the present study was to investigate whether a high cholesterol diet supplemented with aspartate and glutamate may alter lipoproteins cholesterol and apolipoproteins A-1 and B levels in rabbits. RESULTS Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), apolipoprotein A-1 (apoA-1), apolipoprotein B (apoB), atherogenic index (AI) and apoA-1/apoB ratio were determined in 17 male New Zealand white rabbits fed a cholesterol plus corn oil diet (control group) or the same diet supplemented with aspartate and glutamate (Asp+Glu group) for 4 weeks. Both diets were found to increase TC, LDL-C, apoB and AI, while apoA-1/apoB ratio was decreased compared to baseline values. TG did not seem to be affected in the 4 weeks time in both groups. There was a significant increase of HDL-C in Asp+Glu group and a marked decrease of apoA-1 in control group during the study. CONCLUSIONS Oral administration of aspartate and glutamate has been shown to inhibit fatty streak initiation in cholesterol-fed rabbits. The two amino acids did not have any effect on serum TC, LDL-C, TG and apoB concentrations. However, they increased HDL-C and maintained apoA-1 levels. Their antiatherogenic effect probably may be explained by different mechanisms than these related to the atherogenic lipids lowering, and it is possible to involve HDL-C and apoA-1.