Human arginine metabolism during end stage renal disease

The kidneys are the major site for net arg synthesis in the whole body arginine economy. Alterations of the L-arg-NO pathway have been considered responsible for pathophysiologic changes during End Stage Renal Disease (ESRD). To begin to explore in vivo, human, whole body arginine metabolism in ESRD. we conducted a series of 8 hour, primed, constant intravenous infusions of L-[¹⁵N₂] arginine, L-[¹³C] arginine and L-[¹³C ureido, 5,5²H₂] citrulline pre and post-hemodialysis (HD) in 6 adults (Age 21 to 65y), with terminal ESRD awaiting transplant. Blood and breath samples as well as indirect calorimetry were obtained. Patients received adequate protein and energy intake. Plasma arg fluxes with the ¹⁵N₂ label were 75±20 and 98±20 umol.kg^-1.h^-1: Plasma fluxes for ¹³C arg were 65±16 and 72±19 umol.kg^-1.h^-1 respectively, pre and post-HD for post absorptive state. Plasma citrulline fluxes were 67±19 and 83±12 umol.kg^-1.h^-1 respectively, for postabsorptive state pre and post HD. There were no differences in arg fluxes before and after hemodialysis treatment. These preliminary studies show a significant increase in plasma citrulline fluxes when compared to historical values of 15-20 umol kg^-1.h^-1 reported in healthy controls. This finding is consistent with increased plasma citrulline observed in these patients. Despite ESRD, values for plasma arg fluxes were similar to those reported in healthy adults, indicating that whole body arg turnover is maintained despite the absence of renal function. There was no difference between the pre or post-HD.