| Autor: |
Nyborg C; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Department of Vascular Surgery, Oslo University Hospital, 0424 Oslo, Norway., Bonnevie-Svendsen M; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Department of Vascular Surgery, Oslo University Hospital, 0424 Oslo, Norway., Melsom HS; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Department of Vascular Surgery, Oslo University Hospital, 0424 Oslo, Norway., Melau J; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Department of Vascular Surgery, Oslo University Hospital, 0424 Oslo, Norway.; Department of Prehospital Care, Vestfold Hospital Trust, 3103 Toensberg, Norway., Seljeflot I; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Center for Clinical Heart Research, Department of Cardiology, Oslo University Hospital, 0424 Oslo, Norway., Hisdal J; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.; Department of Vascular Surgery, Oslo University Hospital, 0424 Oslo, Norway. |
| Abstrakt: |
Endothelial vasodilatory function is dependent on the NO synthesis from L-arginine by endothelial NO-synthetase (eNOS). eNOS can be inhibited by asymmetric dimethylarginine (ADMA) by competitive inhibition on the binding site, and symmetric dimethylarginine (SDMA) can reduce the L-arginine availability intracellularly through competing for transport over the cellular membrane. To study the NO synthesis after prolonged exercise, we assessed circulatory L-arginine, the L-arginine/ADMA ratio, and SDMA before, after, and on the day after the Norseman Xtreme triathlon, an Ironman distance triathlon. We found significantly reduced levels of L-arginine and the L-arginine/ADMA ratio and increased levels of SDMA after the race (all p < 0.05). L-arginine rose toward baseline levels the day after the race, but ADMA increased beyond baseline levels, and SDMA remained above baseline the day after the race. The reduced levels of L-arginine and the L-arginine/ADMA ratio, and increased SDMA, after the race indicate a state of reduced capability of NO production. Increased levels of ADMA and SDMA, and reduced L-arginine/ADMA ratio, as seen the day after the race, are known risk markers of atherosclerosis and warrant further studies. |
