A method for separation of middle molecules by high performance liquid chromatography: application in studies of glucuronyl-o-hydroxyhippurate in normal and uremic subjects.

An efficient separation of middle molecules (Mr 350-2000) was obtained by gel permeation HPLC and ion exchange HPLC. These methods were used to analyze glucuronyl-o-hydroxyhippurate (GOHH), a metabolite previously identified in plasma and urine from uremic patients. The concentrations of GOHH in normal and uremic urine and in uremic plasma increased markedly after the ingestion of salicylate. Oral ingestion of phenylalanine and tyrosine did not influence GOHH in plasma and urine. The results indicate that GOHH is an endogenous metabolite in normal and uremic subjects, as well as a novel metabolite of salicylate.