Gender Differences in VLDL1 and VLDL2 Triglyceride Kinetics and Fatty Acid Kinetics in Obese Postmenopausal Women and Obese Men

Context: High plasma triglycerides (TG) have been shown to be independent and better predictors of cardiovascular disease than low-density lipoprotein (LDL) cholesterol in women. This may be due to gender differences in very-low-density lipoprotein 1 (VLDL1)- and VLDL2-TG and fatty acid kinetics. Objective: Our objective was to investigate whether there are differences in VLDL1- and VLDL2-TG and fatty acid kinetics in obese men and postmenopausal women, a high risk group for cardiovascular disease. Research Design and Methods: Stable isotopes techniques were used to measure fasting palmitate rate of appearance, metabolic clearance rate, oxidation rate, and nonoxidative disposal rate, VLDL1-TG and VLDL2-TG fractional catabolic rate (FCR) and production rate (PR). Whole-body fat distribution was measured by magnetic resonance imaging. Participants: Participants included 10 postmenopausal obese women and eight obese men matched for age, body mass index, and fasting plasma TG. Results: The women had lower visceral fat and higher sc fat than the men (P < 0.001 and P < 0.002). Palmitate rate of appearance, metabolic clearance rate, nonoxidative disposal rate, and oxidation rate corrected for resting energy expenditure were greater in the women than the men (all P < 0.03). VLDL2-TG PR corrected for fat-free mass was higher in the women (P < 0.001). VLDL2-TG and VLDL2-cholesterol pools were higher in the women (P < 0.001 and P < 0.008). VLDL1-TG FCR and PR and VLDL2-TG FCR were not different between genders. Conclusion: Fatty acid and VLDL2-TG flux is higher in postmenopausal obese women than in obese men matched for fasting plasma TG levels.