Levels and Significance of Erythrocyte Purine Enzymes in Hyperuricemia

Summary

To examine possible relationships among purine enzyme patterns in hy-peruricemia and gout, purine enzyme activities were measured in erythrocytes from young adults who were either normouricemic, hyperuricemic, or had a family history of gout. The purine enzymes whose activities were measured included adenine phospho-ribosyltransferase (APRT), hypoxanthine phosphoribosyltransferase (HPRT), adeno-sine deaminase (AD), adenosine kinase (AK), and 5'-nucleotidase. AD and AK activities were not different among the normouricemic, hyperuricemic, or family history of gout groups. The activity of APRT was significantly higher in the group with a family history of gout compared with the normouricemics, and the activity of HPRT was significantly lower in the hyperuricemic and family history of gout groups compared with the normouricemics. The ratio of APRT/HPRT was significantly greater in 66% of those subjects who had a family history of gout and were also hyperuricemic compared with normouricemics without a family history of gout. No measurable 5'-nucleotidase was found in human erythro-cyte hemolysates. The lack of correlation between the activities of AD and AK in erythrocytes and plasma uric acid levels may be due to the lack of 5'-nucleotidase in this tissue since in the absence of 5'-nucleo-tidase the erythrocyte has a minimal capacity to break down nucleotides.

These studies were supported by Grant No. AM-16726 from the U.S. Public Health Service. Special thanks are expressed to Antone F. Salel, M.D., Department of Internal Medicine, Section of Cardiovascular Medicine, University of California, Davis, Medical School, for his cooperation in providing blood samples, and to Randy H. Shaffer for his valuable technical assistance.