THE LEPR GENE AND BODY FAT AND LEPTIN RESPONSES TO ENDURANCE TRAINING IN THE HERITAGE FAMILY STUDY.

1899 The role of the leptin receptor gene (LEPR) in the response of body fat and plasma leptin to exercise training was investigated in 742 subjects (parents and adult offspring; 260 Blacks and 482 Caucasians) who completed 20 weeks of endurance training. Three LEPR polymorphisms were typed: K109R (exon 4), Q223R (exon 6) and K656N (exon14). Subcutaneous fat (sum of 8 skinfolds), percent body fat, fat mass (FM) and fat free mass assessed by underwater weighing, and plasma leptin were measured before (baseline) and after training. The difference between pre- and post-training values (Δ) was computed and adjusted within each race for sex, age and baseline value. In both races, and within each sex by generation group, training resulted in significant body fat reductions, that were correlated with changes in leptin. Changes in leptin reached significance only in Caucasian males. A significant (p < .01) race by gene interaction was observed for the effects of the Q223R polymorphism on ΔFM and Δleptin. In Blacks, changes in FM and leptin were lower in homozygous for the R allele compared to carriers of the Q allele, while no such effects were observed in Caucasians. There were no effects of the K109R and K656N polymorphisms. Correlations between ΔFM and Δleptin were also different among the Q223R genotypes. These results suggest race differences in the modulation by the LEPR gene of the body fat and plasma leptin responses to exercise training. Supported by NIH