triacylglycerol kinetics in endotoxic rats with suppressed lipoprotein lipase activity hypertriglyceridemia observed in animals after bacterial endotoxin administration and some forms of sepsis can result from increased hepatic triacylglycerol tg output or decreased tg clearance by extrahepatic tissues to differentiate between these two possibilities tg and free fatty acid ffa kinetics were determined in control and endotoxininjected 0105 mg100 g rats 18 h after treatment plasma tg and ffa kinetics were assessed by a constant intravenous infusion with 9103hpalmitatelabeled very lowdensity lipoprotein and 114cpalmitate bound to albumin respectively in addition lipoprotein lipase lpl activity was determined in heart skeletal muscle and adipose tissue as well as in postheparin plasma of functionally hepatectomized adrenalectomized and gonadectomized rats plasma ffa acid concentrations were slightly increased in endotoxintreated rats but their turnover did not differ from control endotoxintreated rats had a threefold increase in plasma tg concentrations and decreased heart skeletal muscle and postheparin plasma lpl activity plasma tg turnover was decreased indicating that hypertriglyceridemia was not due to an increased tg output by the liver instead the endotoxininduced increase in plasma tg concentration was a consequence of the 80 reduction in tg metabolic clearance rate thus suppression of lpl activity in endotoxic animals impairs tg clearance resulting in hypertriglyceridemia furthermore endotoxin administration reduced the delivery of tgffa to extrahepatic tissues because hepatic synthesis and secretion of tg from plasma ffa was decreased and lpl activity was suppressed