1. We have studied purine metabolism in renal failure using high-pressure liquid chromatography to determine metabolite concentrations in erythrocytes and plasma, and microradiochemical assays of enzyme activity in erythrocytes.
2. the mean activities of some of the enzymes involved in purine metabolism were raised in renal failure. Significant elevations of adenylate kinase (EC 22.214.171.124), purine nucleoside phosphorylase (EC 126.96.36.199), hypoxanthine phosphoribosyltransferase (EC 188.8.131.52) and adenosine deaminase (EC 184.108.40.206) but not of adenine phosphoribosyltransferase (EC 220.127.116.11) and ribosephosphate pyrophosphokinase (phosphoribosylpyrophosphate synthetase; EC 18.104.22.168) activities were demonstrated. However, there was an overlap between results from patients with renal failure and normal (control) subjects. Erythrocyte phosphoribosylpyrophosphate levels were also unchanged.
3. Erythrocyte nucleotide concentrations especially those of inosine were raised in renal failure.
4. the plasma inosine was reduced in renal failure.
5. the significance of these changes is discussed.