AGE, EXERCISE, DIET, AND LIPOPROTEIN METABOLISM

The overall objective of this proposal is to examine alterations in the plasma lipoprotein profile, hepatic lipoprotein producton, skeletal muscle and adipose tissue lipoprotein lipase activity, and vessel and tissue pathology as influenced by age, exercise, and hyperlipemia. Our experimental design allows a longitudinal assessment of these three factors separately and together. In addition, our design is such that the effect of exercise on lipid and lipoprotein pathophysiology can be studied subsequent to the existance of a relatively long-term diet induced hyperlipemia. A compositional analysis (cholesterol--esterified and unesterified, phospholipid, triglyceride, and protein) of plasma very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL), and hepatic VLDL, LDL and HDL will be done following isolation of the lipoprotein classes by preparative ultracentrifugation. Skeletal muscle and adipose tissue lipoprotein lipase activity will be measured. Total carcass, liver, atora, and adipose tissue cholesterol will be determined. A histological examination of the aorta will be done. Fatty infiltration of the liver, heart, and kidney will be assessed by histological examination. These studies will be of particular importance in advancing our understanding of the influence of age on the plasma lipoprotein profile and hepatic lipoprotein production. Moreover, this proposed investigation will clarify the influence of hyperlipemia and exercise on modifying changes in lipid and lipoprotein metabolism and pathophysiology associated with aging.