JOURNAL OF SEXUAL MEDICINE, vol.3, no.1, pp.69-75, 2006 (SCI-Expanded)
Introduction. Endothelial-derived nitric oxide (NO), which is produced by endothelial nitric oxide synthase (eNOS) in response to increased blood flow, maintains the tumescence phase of erection. The eNOS gene is located on the seventh somatic chromosome and the polymorphism of this gene has been reported to cause changes in the structure of enzyme system, resulting in disturbance of its activity.