The bradykinin β2 receptor (BDKRB2) and endothelial nitric oxide synthase 3 (NOS3) genes and endurance performance during Ironman Triathlons
MRC/UCT Research Unit for Exercise Science and Sports Medicine, Medical Research Council of South Africa, University of Cape Town, PO Box 115, Newlands 7725, South Africa; Department of Human Biology, University of Cape Town, PO Box 115, Newlands 7725, South Africa; Molecular Genetics Department B, Laboratory of Forensic Genetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus; Cardiovascular Diagnostic Centre, Nicosia, Cyprus
We have previously shown that the insertion allele of the angiotensin-converting enzyme (ACE) gene was over-represented in the fastest South-African-born finishers of the South African Ironman Triathlons. As ACE is a component of the skeletal muscle kallikrein-kinin system (KKS), the aim of this study is to determine if there are any further associations between polymorphisms within the BDKRB2 and NOS3 genes, which encode for the KKS components, bradykinin β2 receptor and nitric oxide synthase, respectively, and ultra-endurance performance during the Ironman Triathlons. Four-hundred and forty-three male Caucasian triathletes who completed the 2000 and/or 2001 South African Ironman Triathlons and 203 healthy Caucasian male control subjects were genotyped for the functional -9/+9 polymorphism within exon 1 of the BDKRB2 gene and the G894T NOS3 gene polymorphisms. The BDKRB2 -9/-9 genotype occurred at a significantly higher frequency when the triathlete group (27.0%) was compared with the control group (19.3%, P =0.035). When divided into tertiles, there was also a significant linear trend for the NOS3 GG genotype distribution among the fastest (35.0%), middle (40.4%) and slowest (46.9%) finishers (P =0.039). The overall finishing times of the triathletes with an NOS3 GG genotype together with a BDKRB2 + 9 allele were significantly slower than those with other genotype combinations (P = 0.001). The NOS3/BDKRB2 genotype (β = -0.150, B = -31.48, P=0.002), together with body mass index and age, accounted for 14.6% of the variance in the overall race time for the triathlon. In conclusion, both the NOS3 and BDKRB2 genes are associated with the actual performance during the Ironman Triathlons. © 2006 Oxford University Press.
bradykinin B2 receptor; endothelial nitric oxide synthase; analysis of variance; article; athlete; controlled study; DNA polymorphism; endurance sport; exon; functional assessment; functional genomics; gene frequency; genetic association; genetic variability; genotype; human; human experiment; kallikrein kinin system; male; multivariate analysis; normal human; priority journal; protein expression; protein function; South Africa; statistical significance; triathlon; Adult; Bicycling; Gene Frequency; Genotype; Humans; Male; Multivariate Analysis; Nitric Oxide Synthase Type III; Physical Endurance; Receptor, Bradykinin B2; Running; South Africa; Sports; Swimming