Influence of body fat distribution on free fatty acid metabolism in obesity.

TLDR

Differences in free fatty acid metabolism may reflect adipocyte heterogeneity that influences metabolic abnormalities in distinct obesity phenotypes. The study aimed to determine whether body fat distribution causes specific abnormalities in free fatty acid metabolism. Palmitate turnover was measured in 10 upper‑body obese, 9 lower‑body obese, and 8 non‑obese women under basal, epinephrine‑stimulated, and insulin‑suppressed conditions. Upper‑body obese women exhibited higher basal palmitate turnover but a blunted epinephrine‑stimulated lipolytic response, and both obesity types showed impaired insulin suppression of FFA turnover, underscoring the need to characterize obese subjects before studies.

Abstract

In order to determine whether differences in body fat distribution result in specific abnormalities of free fatty acid (FFA) metabolism, palmitate turnover, a measure of systemic adipose tissue lipolysis, was measured in 10 women with upper body obesity, 9 women with lower body obesity, and 8 nonobese women under overnight postabsorptive (basal), epinephrine stimulated and insulin suppressed conditions. Results: Upper body obese women had greater (P less than 0.005) basal palmitate turnover than lower body obese or nonobese women (2.8 +/- 0.2 vs. 2.1 +/- 0.2 vs. 1.8 +/- 0.2 mumol.kg lean body mass (LBM)-1.min-1, respectively), but a reduced (P less than 0.05) net lipolytic response to epinephrine (59 +/- 7 vs. 79 +/- 5 vs. 81 +/- 7 mumol palmitate/kg LBM, respectively). Both types of obesity were associated with impaired suppression of FFA turnover in response to euglycemic hyperinsulinemia compared to nonobese women (P less than 0.005). These specific differences in FFA metabolism may reflect adipocyte heterogeneity, which may in turn affect the metabolic aberrations associated with different types of obesity. These findings emphasize the need to characterize obese subjects before studies.