The renin angiotensin system (RAS) is emerging as a prominent factor in the development of experimental atherosclerosis. We have previously demonstrated that the RAS is profoundly activated in hypercholesterolemia. This was demonstrated in LDLR-/-mice fed a saturated fat enriched diet and manifested as increased plasma concentrations of angiotensinogen and angiotensin peptides; especially angiotensin Ⅱ(AngⅡ).