Identification and Determination of Phenylacetylglutamine, a Major Nitrogenous Metabolite in Plasma of Uremic Patients

Phenylacetylglutamine, a constituent of normal urine, was identified and quantitated in plasma ultrafiltrates from uremic patients. Its concentration ranged from 18 to 366 mumol/l, which shows a greater individual variation than those for the concentrations of urea and creatinine. The plasma level was reduced by hemodialysis. In ultrafiltrates from healthy subjects phenylacetylglutamine could not be detected with the methods used. Thus, it is a major nitrogenous metabolite that accumulates in uremia. A reverse phase HPLC method for the quantitative determination of phenylacetylglutamine in plasma ultrafiltrates is described.