Associations Between Genetic Variants in MCT2 (rs3763980, rs995343, rs3763979) and MCT4 (rs11323780) with Blood Lactate Kinetics Before and After Supramaximal Exercise

Despite progress in understanding the role of monocarboxylate transporters (MCTs) in lactate (LA) accumulation and removal, it remains unclear whether <i>MCT2</i> and <i>MCT4</i> variants enhance LA utilization. This study assessed associations between <i>MCT2</i> (rs3763980, rs995343, rs3763979) and <i>MCT4</i> (rs11323780) polymorphisms and LA concentration. A total of 337 male athletes from the Czech Republic and Poland, divided into elite, sub-elite, and physically active individuals, completed two all-out Wingate tests. Before these tests, DNA was collected and analyzed for single-nucleotide polymorphisms (SNPs). LA concentrations were measured before and after the tests. <i>MCT2</i> rs995343 showed the broadest associations. It was significantly associated with resting LA (LArest) in the overall cohort (codominant: false discovery rate (FDR)-adjusted <i>p</i> = 0.04; dominant: FDR-adjusted <i>p</i> = 0.03) and with peak LA concentration (LAmax), accumulation (ACC), and clearance (DCC) in the physically active group (all models: FDR-adjusted <i>p</i> = 0.02-0.04). <i>MCT2</i> rs3763980 was associated with LArest in the overall group (codominant and recessive: FDR-adjusted <i>p</i> = 0.04). <i>MCT2</i> rs3763979 was associated with LArest (FDR-adjusted <i>p</i> = 0.009-0.003) and LA30' (FDR-adjusted <i>p</i> = 0.003-0.04) in the overall and physically active cohorts. <i>MCT4</i> rs11323780 was associated with LArest in elite athletes (recessive: FDR-adjusted <i>p</i> = 0.03) and with ACC in the physically active group (codominant and recessive: FDR-adjusted <i>p</i> = 0.03). These findings indicate that <i>MCT</i> polymorphisms contribute to variability in LA metabolism, influencing anaerobic performance and recovery.