Determination of the endogenous component of alimentary lipemia

Alimentary triglyceridemia was induced in 20 normal male volunteers by ingestion of 100 g of peanut butter (triglyceride 50%) with 2 slices of bread and 2 cups of water or unsweetened coffee. By comparison of the postprandial triglyceride fatty acid pattern with that of the ingested fat and the fasting serum, the alimentary lipemia has been partitioned into its endogenous and exogenous triglyceride components. The mean increase in serum triglyceride at 4 hr after a fat meal was 130 mg/100 ml, 93 % of which was derived from the absorbed fat. The mean endogenous contribution rose slightly at the 4-hr point. However, subjects whose alimentary lipemia was more than double the fasting value invariably showed an increase in endogenous contribution, whereas those whose post-prandial value was less than twice fasting exhibited a decrease in endogenous lipemia. The increases of both endogenous and exogenous components seen with the greater lipemia elevations suggest saturation of a clearing mechanism. Addition of 100 g of sucrose to the test meal produced variable and insignificant changes in the total lipemia as compared with the nonsucrose meal. However, a small but probably significant decrease occurred in the endogenous component of the triglyceride fatty acids. Such a decrease appears to be associated with a decrease in endogenous fatty acid production.