Postprandial leg uptake of triglyceride is greater in women than in men

Abstract

The postprandial excursion of plasma triglyceride (TG) concentration is greater in men than in women. In this study, the disposition of dietary fat was examined in lean healthy men and women ( n = 8/group) in either the overnight-fasted or fed (4.5 h after breakfast) states. A [14C]oleate tracer was incorporated into a test meal, providing 30% of total daily energy requirements. After ingestion of the test meal, measures of arteriovenous differences in TG and14C across the leg were combined with needle biopsies of skeletal muscle and adipose tissue and respiratory gas collections to define the role of skeletal muscle in the clearance of dietary fat. The postprandial plasma TG and14C tracer excursions were lower ( P = 0.04) in women than in men in the overnight-fasted and fed states. Women, however, had significantly greater limb uptake of total TG compared with men on both the fasted (3,849 ± 846 vs. 528 ± 221 total μmol over 6 h) and fed (4,847 ± 979 vs. 1,571 ± 334 total μmol over 6 h) days. This was also true for meal-derived14C lipid uptake.14C content of skeletal muscle tissue (μCi/g tissue) was significantly greater in women than in men 6 h after ingestion of the test meal. In contrast,14C content of adipose tissue was not significantly different between men and women at 6 h. The main effect of nutritional state, fed vs. fasted, was to increase the postmeal glucose ( P = 0.01) excursion (increase from baseline) and decrease the postmeal TG excursion ( P = 0.02). These results support the notion that enhanced skeletal muscle clearance of lipoprotein TG in women contributes to their reduced postprandial TG excursion. Questions remain as to the mechanisms causing these sex-based differences in skeletal muscle TG uptake and metabolism. Furthermore, nutritional state can significantly impact postprandial metabolism in both men and women.