Androgen receptor gene polymorphisms and maximal fat oxidation in men. A longitudinal study.

Introduction: The aims of this study were i) to evaluate if extreme CAG and GGN repeat polymorphisms of the androgen receptors (AR) influence body fat mass, its regional distribution, resting metabolic rate (RMR), resting and maximal fat oxidation capacity (MFO) and fat tissue accumulation after 6.4 years of follow up and ii) to determine if these differences are explained by changes in maximal oxygen uptake (VO2max).Potential associations between AR polymorphisms and serum concentration of leptin, free testosterone and osteocalcin were also examined.Methods: CAG and GGN repeats length were measured in 319 men (mean±SD: 28.3±7.6 years). From these, we selected the subjects with extreme short (CAGS≤19; n=7) and long (CAGL≥24; n=10) CAG repeats, and the subjects with short (GGNS≤22; n=9) and long (GGNL≥25; n=10) GGN repeats.Results: CAGS and CAGL subjects had similar RMR and accumulated comparable amounts of fat tissue over 6.4 ± 1.0 years of follow-up. However, CAGL showed higher MFO and total lean mass than CAGS (p<0.05). Men with GGNS accumulated greater amount of total fat mass than men with GGNL, particularly in the trunk region seven years later. This concurs with a trend for a greater MFO in the GGNL group (P=0.06), who accumulated less fat mass. Free testosterone was associated with MFO in absolute values (r=0.45; p<0.05) and MFO per kg of lower extremity lean mass per height squared (r=0.35; p<0.05).Conclusions:CAG and GGN repeats polymorphisms may influence muscle fat oxidation capacity and may have a role in the accumulation of fat over the years.