Moderate exercise reduces postprandial triacylglycerol concentrations, which are a risk marker for coronary heart disease. The present study sought to determine the qualitative nature of exercise-induced changes in lipid metabolism and their association (if any) with changes in factor VII activation. Eleven normotriglyceridaemic men, aged 51.7±6.1 years (mean±S.D.), participated in two oral fat tolerance tests after different pre-conditions: control (no exercise), and exercise (90 min of brisk walking the day before). Venous blood samples were obtained in the fasted state and for 8 h after ingestion of a high-fat meal (1.32 g of fat, 1.36 g of carbohydrate, 0.30 g of protein and 10 mg of [1,1,1-13C] tripalmitin·kg-1 body mass). Prior exercise reduced postprandial plasma triacylglycerol concentrations by 25±3% (mean±S.E.M.), with lower concentrations in the Svedberg flotation rate (Sf) 20–400 (very-low-density lipoprotein) fraction accounting for 79±10% of this reduction. There was no effect on plasma factor VII coagulant activity or on the concentration of the active form of factor VIIa. Prior exercise increased postprandial serum 3-hydroxybutyrate and plasma fatty acid concentrations, decreased serum postprandial insulin concentrations and increased exogenous (8 h 13C breath excretion of 15.1±0.9% of ingested dose compared with 11.9±0.8%; P = 0.00001) and endogenous postprandial fat oxidation. These data raise the possibility that reduced hepatic secretion of very-low-density lipoprotein plays a role in the attenuation of plasma triacylglycerol concentrations seen after exercise, although it is possible that increased triacylglycerol clearance also contributes to this effect.
Leptin Augments the Acute Suppressive Effects of Insulin on Hepatic Very Low-Density Lipoprotein Production in Rats
