Endothelium-derived relaxing factor


Endothelium-derived relaxing factor is a name for a substance Robert F. Furchgott discovered had the eponymous properties. Today, it is firmly established this substance is nitric oxide. Endothelium produces NO which then diffuses to the vascular smooth muscle tissue, although there seems to be evidence that vasodilation may also be of neuronal origin, rather than endothelial. NO is produced by the enzyme nitric oxide synthase and it relaxes smooth muscle tissue by promoting the synthesis of cGMP.
Furchgott was a co-recipient of the 1998 Nobel Prize in Medicine with his colleagues Louis J. Ignarro and Ferid Murad. Shortly after his death in May 2009, Furchgott's website at SUNY Downstate Medical Center continued to state that his group was "investigating whether the endothelium-derived relaxing factor is simply nitric oxide or a mixture of substances".