Estrogen affects energy metabolism via upregulation of mitochondrial biogenesis and angiogenesis in muscular tissue. Recently, it was reported that TT genotype of rs1271572 of estrogen receptor-beta (ESR2) gene resulted in reduction of the transcription activity in the ESR2. Therefore, the ESR2 gene polymorphism may have potential impacts on cardiorespiratory fitness. However, the effect of the ESR2 genotype (rs1271572) on the cardiorespiratory fitness and gender difference of influence with the genotype remain unclear.
PURPOSE: To determine the effect of ESR2 gene polymorphism (rs1271572) on cardiorespiratory fitness and gender difference of influence with the genotype in the Japanese adults.
METHODS: Two hundred sixty Japanese men (19-85 yrs, average age; 45.6±17.2 yrs, mean±SD) and six hundred six women (18-84 yrs, average age; 48.7±16.4 yrs) participated in a cross-sectional study. ESR2 (rs1271572, G>T; transposition in the promoter region) polymorphism was determined by real-time PCR with Taqman probe. As an index of cardiorespiratory fitness, we measured peak oxygen uptake (VO2peak) during an incremental cycle ergometer exercise test.
RESULTS: No significant differences in the allelic frequencies of the polymorphism was detected between the genders (men: G allele=0.57; women: G allele=0.60), and these frequencies also did not deviate from the predicted Hardy-Weinberg equilibrium. In women, the VO2peak of individuals with the TT genotype of rs1271572 were significantly lower than those of other genotypes (GG; 32.0±7.5, GT; 30.8±6.9, TT; 29.8±7.5 ml/kg/min., mean ±SD) after adjustment for confounders such as smoking status, drug-taking status and %fat. However, no differences of VO2peak among the genotypes were observed in men (GG; 37.0±10.7, GT; 36.6±9.6, TT; 36.6±8.8 ml/kg/min.).
CONCLUSIONS: TT genotype of ESR2 gene (rs1271572) is associated with lower cardiorespiratory fitness in Japanese women but is not associated in men. These results suggest that the effect of the ESR2 genotype on the cardiorespiratory fitness is differed between genders.