Zinc in human blood cells: normal values and abnormalities associated with liver disease.

Studies of the biochemistry of zinc have produced results which are widely divergent because of difficulties in methodology. However, techniques have evolved so that general agreement now exists that dithizone methods give reliable and reproducible measurements of zinc in erythrocytes and sera, and that acid extraction of the zinc from these biological materials produces more consistent and accurate results than wet-ashing or dry-ashing methods of preparing specimens for dithizone determination of zinc (1-4). Although normal values for erythrocyte and serum zinc have been established, the zinc content of leukocytes from normal persons using the acid extractiondithizone method has not been evaluated in the past. Patients with hepatic cirrhosis have been found to have low serum zinc levels (5, 6), zincuria (7), and decreased concentrations of zinc in liver tissue (6, 7). Vallee, Wacker, Bartholomay and Hoch (7) have postulated that these disturbances of zinc metabolism may be due to inhibition and perhaps to degradation of the zinc metalloenzymes, alcohol and glutamic dehydrogenases, because of excessive ethanol ingestion. However, there has been no direct evidence of altered intracellular zinc levels in patients with liver disease. The purposes of this study were to extend the application of the acid extraction-dithizone method for the determination of zinc to human leukocytes, to re-examine critically the levels of zinc in blood cells of normal persons, and to investigate the zinc content of the erythrocytes and leukocytes of patients with cirrhosis.