Lipid-regulating action of gemfibrozil in the stroke-prone spontaneously hypertensive rat.

1. Gemfibrozil (Lopid) is extensively used as lipid-regulating agent in the Western World, and its beneficial effect is demonstrated in human studies such as the Helsinki Heart Study. However, the mechanism of its hypolipidaemic action is not fully understood. In the present paper, to elucidate the hypolipidaemic mechanism, we examined the effects of gemfibrozil on lipid metabolism in the normocholesterolaemic and hypercholesterolaemic stroke-prone spontaneously hypersensitive rat (SHRSP). 2. Gemfibrozil effectively increased high density lipoprotein (HDL) subfraction rich in apoE (apoE-HDL) and significantly decreased very low density lipoprotein (VLDL) in normocholesterolaemic SHRSP. In the liver of normocholesterolaemic SHRSP, gemfibrozil significantly reduced the activity of microsomal acyl-CoA:cholesterol acyltransferase. 3. Gemfibrozil markedly reduced atherogenic beta-very low density lipoprotein (beta-VLDL) and low density lipoprotein (LDL) in hypercholesterolaemic SHRSP fed a high-fat and high-cholesterol diet (HFC diet). On the other hand, it significantly increased the contents of apoA-I, A-IV and E in the HDL fraction compared with the control group, suggesting that gemfibrozil effectively increases anti-atherogenic HDL subfractions rich in apoA-I, A-IV or E. In the liver of hypercholesterolaemic SHRSP, gemfibrozil markedly prevented lipid accumulation.