LIPOLYSIS IN ELDERLY POSTMENOPAUSAL WOMEN

The rate of fat oxidation at rest decreases with age in women. The mec hanisms for this decrease are not clear. Theoretically, a decrease in the availability of fatty acids could explain the decline in fat oxida tion, In consequence, the in vivo rate of production of fatty acids as a proxy for lipolysis was measured in 21 healthy women. Eleven of the volunteers were elderly (>65 years) and 10 were young <24 years), and all were characterized for body composition. The nonadjusted rate of delivery of fatty acids into the systemic circulation was similar amon g elderly and young individuals (609 +/- 80.3 v 597 +/- 69.9 mu mol/mi n, respectively, P > .1), When lipolysis was adjusted for the differen ces in fat-free mass using analysis of covariance (ANCOVA), rates were slightly increased in the elderly group (626 +/- 80 mu mol/min) and d ecreased in the young group (578 +/- 84 mu mol/min), but remained nons tatistically significant, It is concluded that mechanisms other than l ipolysis must explain the decrease of fat oxidation in aging women, ie , a decrease in the capacity of muscle to oxidize far and/or a decreas e in its capacity for transport of long-chain fatty acids. Copyright 1 997 by W.B. Saunders Company.