It is proposed to study the function and metabolism of the various apolipoproteins. The synthesis and the rate of removal of the apolipoproteins will be studied under normal conditions and during hyperlipidemia. It is proposed that hyperlipoproteinemias could be characterized according to their apolipoprotein profile. An apolipoprotein profile is defined as a quantitative assessment of serum apolipoprotein concentrations and apolipoprotein distributions among the various lipoprotein classes and their correlation with serum lipid values. Apolipoprotein profiles will be studied in experimentally induced hyperlipoproteinemic rats and monkeys, to demonstrate the difference in apolipoprotein patterns between control and hyperlipoproteinemic animals. The changes in apolipoprotein profiles between hyperlipoproteinemias of different origin will be compared, and the effect of hypolipidemic drugs will be studied. The development of hyperlipoproteinemia and corresponding changes in apolipoprotein profiles will be correlated with the development of atherosclerosis. The presence of apolipoproteins in the atherosclerotic tissue will be determined and its concentration and flux will be correlated with the serum apolipoproteins. BIBLIOGRAPHIC REFERENCES: Bar-On, H., Roheim, P.S. and Eder, H.A. Serum Lipoproteins and Apolipoproteins in Rats With Streptozotocin-Induced Diabetes. J. Clin. Invest. 57: 714-721, 1976. Roheim, P.S., Edelstein, D. and Pinter, G.G. Apolipoproteins in Rat Serum and Renal Lymph. Proc. Natl. Acad. Sci. 73: May, 1976.