The Trp64Arg polymorphism of the beta 3-adrenergic receptor gene is not associated with training-induced changes in body composition: The HERITAGE Family Study

Objective: To investigate the association between the Trp64Arg polymorphism of the beta3-adrenergic receptor gene and changes in body composition in r esponse to endurance training. Research Methods and Procedures: Adult sedentary white and black subjects p articipating in the HERITAGE Family Study were measured before and after 20 weeks on endurance training for the body mass index, fat mass, percentage of body fat, fat-free mass, sum of eight skinfolds, and subcutaneous, visce ral, and total abdominal fat areas, The association between the Trp64Arg po lymorphism and the response phenotypes, computed as the difference between pre- and post-training values, was tested by analysis of covariance separat ely in men and women. The gene by race interaction term was also tested. Results: No race differences were observed for allelic and genotype frequen cies. Training resulted in significant reduction of body fat in both men an d women. No association of the Trp64Arg polymorphism was observed with trai ning-induced changes for any of the body composition phenotypes in both men and women. Discussion: These results suggest that the Trp64Arg polymorphism of the bet a3-adrenergic receptor gene is not related to changes in body composition i n response to exercise training.