Use of Multicompartmental Models to Measure Rates of Triglyceride Metabolism in Rats.

Specific activities and total radioactivity of liver and serum triglycerides were determined, in glucose-fed rats, at various times after a single intravenous injection of palmitatel-CI4. A multicompartmental model of plasma and liver triglyceride metabolism was constructed which was compatible with the known physiological and biochemical behavior of triglycerides and the observed data. The rates of triglyceride transfer fromone compartment to another and the compartment sizes were calculated using a digital computer. Analysis of the data showed that liver was composed of at least two triglyceride compartments, only one of which secreted triglycerides into plasma. Under these experimental conditions, virtually the entire liver turnover of triglycerides was accounted for as secretion into plasma. This rate of secretion was 0.27 mg/min per 100 g body weight. Only 22y0 of the newly formed liver triglycerides were synthesized directly from plasma free fatty acids.