Fatty Acid Metabolism in the Elderly: Effects of Dehydroepiandrosterone and Testosterone Replacement in Hormonally Deficient Men and Women

Abstract

Aging, low dehydroepiandrosterone (DHEA), and testosterone are associated with increased adiposity and metabolic risk. Treatment with these hormones may improve these abnormalities. The objective of the study was to determine effects of aging, DHEA, or testosterone replacement on adiposity, meal fat partitioning, and postabsorptive lipolysis. This was a cross-sectional, 2-yr, double-blind, randomized, placebo-controlled trial. The study was conducted in the general community. Elderly women and men (>or=60 yr) with low DHEA sulfate (women and men) and bioavailable testosterone (men) concentrations and young adults. Thirty elderly women each received 50 mg DHEA or placebo daily for 2 yr. Thirty elderly men received 75 mg DHEA, 29 received 5 mg testosterone (patch), and 32 received placebo daily for 2 yr. Thirty young women and 32 young men served as controls. In vivo measures of meal fat storage into sc fat, postabsorptive lipolysis, and regional adiposity at baseline and after treatment. At baseline, the elderly had more body fat, greater systemic lipolysis (women, P = 0.0003; men, P < 0.0001) adjusted for resting energy expenditure, greater meal fat oxidation (women, P = 0.026; men, P = 0.0025), and less meal fat storage in sc fat (women, P = 0.0139; men, P= 0.0006). Although testosterone treatment increased meal fat storage into upper- vs. lower-body fat in elderly men, neither hormone affected regional adiposity, meal fat oxidation, or systemic lipolysis. Aging, in the context of low DHEA sulfate (women and men) and bioavailable testosterone (men) concentrations, is associated with changes in meal fat partitioning and postabsorptive lipolysis that are not corrected by DHEA and only partly corrected by testosterone replacement.