Nonoxidative free fatty acid disposal is greater in young women than men

J Clin Endocrinol Metab. 2011 Feb;96(2):541-7. doi: 10.1210/jc.2010-1651. Epub 2010 Dec 1.

Abstract

Context: Large increases in systemic free fatty acid (FFA) availability in the absence of a corresponding increase in fatty acid oxidation can create a host of metabolic abnormalities. These adverse responses are thought to be the result of fatty acids being shunted into hepatic very low-density lipoprotein-triglyceride production and/or intracellular lipid storage and signaling pathways because tissues are forced to increase nonoxidative FFA disposal.

Objective: The objective of the study was to examine whether variations in postabsorptive nonoxidative FFA disposal within the usual range predict insulin resistance and hypertriglyceridemia.

Design: We measured: systemic FFA turnover using a continuous iv infusion of [9-10, (3)H]palmitate; substrate oxidation with indirect calorimetry combined with urinary nitrogen excretion; whole-body and peripheral insulin sensitivity with the labeled iv glucose tolerance test minimal model.

Setting: the study was conducted at the Mayo Clinic General Clinical Research Center.

Participants: Participants included healthy, postabsorptive, nonobese adults (21 women and 21 men).

Interventions: There were no interventions.

Main outcome measures: Nonoxidative FFA disposal (micromoles per minute), defined as the FFA disappearance rate minus fatty acid oxidation.

Results: Women had 64% greater nonoxidative FFA disposal rate than men but a better lipid profile and similar insulin sensitivity. There was no significant correlation between nonoxidative FFA disposal and whole-body sensitivity, peripheral insulin sensitivity, or fasting serum triglyceride concentrations in men or women.

Conclusions: Healthy nonobese women have greater rates of nonoxidative FFA disposal than men, but this does not appear to relate to adverse health consequences. Understanding the sex-specific interaction between adipose tissue lipolysis and peripheral FFA removal will help to discover new approaches to treat FFA-induced abnormalities.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism
  • Adult
  • Anaerobic Threshold / physiology
  • Body Composition / physiology
  • Body Mass Index
  • Calorimetry, Indirect
  • Diet
  • Energy Metabolism / physiology
  • Fatty Acids, Nonesterified / metabolism*
  • Female
  • Glucose Tolerance Test
  • Humans
  • Insulin / physiology
  • Insulin Resistance / physiology
  • Kinetics
  • Lipid Metabolism / physiology
  • Male
  • Oxidation-Reduction
  • Palmitates / blood
  • Sex Characteristics
  • Triglycerides / blood
  • Young Adult

Substances

  • Fatty Acids, Nonesterified
  • Insulin
  • Palmitates
  • Triglycerides