Arg64β3‐Adrenoceptor Variant and the Components of Energy Expenditure

• Published in: Obesity research 2003-04, Vol.11 (4), p.509-511
• Main Authors: Walston, Jeremy, Andersen, Ross E., Seibert, Michael, Hilfiker, Heather, Beamer, Brock, Blumenthal, Jacob, Poehlman, Eric T.
• Format: Article
• Language: eng ; jpn
• Subjects: energy expenditure; genetic variation; gut motility; resting metabolic rate; thermic effect of feeding
• ISSN: 1071-7323; 1550-8528
• DOI: 10.1038/oby.2003.71

Objective: To determine Trp64Arg β3‐adrenoceptor genotype‐specific differences in the components of energy expenditure. Hypothesis: We hypothesized that resting metabolic rate (RMR) and physical activity levels would be lower and that thermic effect of feeding (TEF) would be higher in those with the Arg64 allele. Research Methods and Procedures: RMR and TEF were measured by indirect calorimetry, physical activity by questionnaire, and total energy expenditure by the doubly labeled water method. Genotype‐specific measures were compared using ANOVA and analysis of covariance (ANCOVA). Results: RMR in Arg64 homozygotes was significantly lower than in Trp64 homozygotes [Arg64, 1373 ± 259 kcal/d (n = 15) vs. Trp64Arg, 1538 ± 238 kcal/d (n = 25) vs. Trp64, 1607 ± 290 kcal/d (n = 22); p < 0.01]. TEF was significantly higher in Arg64 homozygotes compared with Trp64 homozygotes (Arg64, 359 ± 28 kcal/d; Trp64Arg, 322 ± 22 kcal/d; and Trp64, 279 ± 23 kcal/d; p < 0.05). No differences were identified between genotypes in physical activity or in total energy expenditure. Discussion: Our results suggest that the Arg64 β3‐adrenoceptor allele contributes significantly to the genetic variability in both RMR and TEF.