LAUSR

This study aimed to clarify 1) the influence of genetic polymorphisms in the cytochrome P450 aromatase gene (CYP19A1) on circulating estradiol levels in men and 2) whether estrogen-related genetic polymorphisms, such as the CYP19A1 rs936306 and estrogen receptor-α (ESR1) rs2234693 polymorphisms, predict exercise-induced muscle damage. Serum estradiol levels were examined in young men (n = 167). In a different cohort, serum creatine kinase (CK) activity, an index of skeletal muscle membrane disruption, was analyzed in a 2-days ultramarathon race: baseline, after the first day, and after the second day (114 males and 25 females). Genetic polymorphisms in CYP19A1 rs936306 C/T and ESR1 rs2234693 T/C were analyzed using the TaqMan SNP genotyping assay. Male subjects with the TT genotype of the CYP19A1 polymorphism exhibited significantly higher serum estradiol levels than the C allele carriers. Male runners had significantly higher post-race serum CK activity than female runners. The change in the CK activity during the ultramarathon race was significantly lower in male subjects with the CYP19A1 TT genotype than in those with the CC+CT genotypes, and was correlated with the number of C alleles in ESR1 rs2234693 in male subjects. Furthermore, the genotype scores of these two polymorphisms were significantly correlated with changes in serum CK activity during race (r = ‒0.279, P = 0.003). The results of this study suggest that genetic polymorphisms in CYP19A1 rs936306 influence serum estradiol levels in men, and genetic polymorphisms in CYP19A1 and ESR1 are associated with serum CK activity in men.