Study is designed to establish the relationship of compartment distribution of nitric oxide during major changes in vascular resistance in the peripheral and renal circulation in humans with cirrhosis before and after liver transplantation. The project uses a novel instrumentation system capable of analyzing quantitatively all forms of NO in plasma and red cells. The hypothesis is reversal of the vasodilation of end-stage liver disease and the transition to vasocontriction underlying post-transplant hypertension is closely related to alterations of endotheleal generation of nitric oxide, which will be reflected by changes in both levels and compartmental distribution of NO in plasma and red cells.