Catecholamine pathway gene variation is associated with norepinephrine and epinephrine concentrations at rest and after exercise

OBJECTIVETo examine the hypothesis that genetic variation in enzymes and transporters associated with synthesis, storage, release, and metabolism of catecholamines contributes to the interindividual variability in plasma catecholamine concentrations at rest and after exercise. METHODSWe measured plasma norepinephrine (NE) and epinephrine concentrations at rest and after a standardized exercise protocol in 165 healthy individuals (60% White, 40% African-American) and examined 29 functional or common variants in 14 genes involved in synthesis, transport, or metabolism of catecholamines. We examined the relationship between genotypes and NE concentrations at rest and the increase after exercise (ΔNE) by multiple linear regression with adjustment for covariates [age, race, sex, BMI, fitness, and resting NE (for ΔNE)]. As a secondary outcome, we carried out similar analyses for epinephrine concentrations. RESULTSThere was large interindividual variability in resting NE (mean, 204±102 pg/ml; range, 39–616 pg/ml) and ΔNE (mean, 256±206 pg/ml; range, −97 to 953 pg/ml). Resting NE was significantly associated with variants of four genesCYB561 (P