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 (VLDL(1))- and VLDL(2)-TG and fatty acid kinetics.

OBJECTIVE

Our objective was to investigate whether there are differences in VLDL(1)- and VLDL(2)-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, VLDL(1)-TG and VLDL(2)-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). VLDL(2)-TG PR corrected for fat-free mass was higher in the women (P < 0.001). VLDL(2)-TG and VLDL(2)-cholesterol pools were higher in the women (P < 0.001 and P < 0.008). VLDL(1)-TG FCR and PR and VLDL(2)-TG FCR were not different between genders.

CONCLUSION

Fatty acid and VLDL(2)-TG flux is higher in postmenopausal obese women than in obese men matched for fasting plasma TG levels.