Lipolysis in elderly postmenopausal women.
The rate of fat oxidation at rest decreases with age in women. The mechanisms for this decrease are not clear. Theoretically, a decrease in the availability of fatty acids could explain the decline in fat oxidation. 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 among elderly and young individuals (609 +/- 80.3 v 597 +/- 69.9 mumol/min, respectively, P > .1). When lipolysis was adjusted for the differences in fat-free mass using analysis of covariance (ANCOVA), rates were slightly increased in the elderly group (626 +/- 80 mumol/min) and decreased in the young group (578 +/- 84 mumol/min), but remained nonstatistically significant. It is concluded that mechanisms other than lipolysis must explain the decrease of fat oxidation in aging women, i.e., a decrease in the capacity of muscle to oxidize fat and/or a decrease in its capacity for transport of long-chain fatty acids.
Calles-Escandón
J
J
Department of Medicine, College of Medicine, University of Vermont, Burlington 05405, USA.
Poehlman
E T
ET
García-Rubí
E
E
D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood / Q000502:physiology*; D000886:Anthropometry; D001786:Blood Glucose / Q000032:analysis; D001824:Body Constitution; D015331:Cohort Studies; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood; D008066:Lipolysis / Q000502:physiology*; D017698:Postmenopause / Q000097:blood / Q000502:physiology*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008055:Lipids