Studies are directed to an understanding of intestinal lipoprotein formation using an in vivo rat model absorbing fat at varying rates. Understanding of the assembly of the surface components of lipoprotein, phospholipid, cholesterol and protein is a particular objective. We plan to characterize the apoproteins of chylomicrons more fully and explore in detail the contribution of the intestine to the formation of very low density lipoproteins (VLDL). We plan to analyze in detail the similarities and differences between VLDL derived from liver and from the intestine. In addition, we plan to reproducibly demonstrate variations in the composition of surface components of lipoprotein during various states of fat transport into mesenteric lymphatics in an attempt to understand the mechanism for such variations. Also, we plan to start studies of the initial metabolic fate of lipoproteins of different composition in recipient animals.