Effects of palm-kernel oil and sunflower-seed oil on serum lipids and atherogenesis in alloxan-diabetic rabbits

Abstract

Groups of metabolically normal (controls) and alloxan-diabetic adult female rabbits were fed semi-synthetic diets containing 40 cal % palm-kernel oil (PKO) or sunflower-seed oil (SSO) for 54 weeks. In contrast to control rabbits fed PKO-diet, the alloxan-diabetic rabbits on this diet, developed no or only a negligible degree of atherosclerosis, although the serum levels of all lipid classes had increased in the diabetic rabbits above that of the controls during almost the whole experimental period. The diabetic rabbits and the controls fed SSO-diet were both free from any significant atherosclerotic involvement in spite of the fact that the SSO-diet appeared unable to suppress the very high levels of the various serum lipid classes induced by the diabetic state. On both diets, the diabetic rabbits showed a significantly higher cholesteryl linoleate/oleate ratio than the controls, which was caused by an increase in the cholesteryl linoleate level in the diabetics. No serious aorta atherosclerosis was found in rabbits with a cholesteryl linoleate/oleate ratio higher than 0.6, although no correlation was found between the atherosclerosis indices and these ratios at values lower than 0.6. Rabbits with cholesteryl linoleate/oleate ratios below 0.6 seemed to run a greater risk of developing atherosclerosis. It is suggested that insulin might be required for atherogenesis in addition to hyperlipemia and hypercholesterolemia.