Citrate Metabolism in Uremia

¹ From the Department of Medicine, Peter Bent Brigham Hospital, and Harvard Medical School, Boston, Massachusetts

Serum citrate concentrations were measured in 19 control subjects and 23 patients with renal failure. In control subjects peripheral arterial (brachial or radial) and peripheral venous (antecubital) citrate levels were equal, averaging 22.6 µg/cc. In uremic patients peripheral arterial citrate concentrations were markedly elevated. Peripheral venous citrate concentrations were often elevated but did not equal arterial values. The average peripheral arteriovenous difference was 13.5 µg/cc. Citrate was infused into three normal subjects and one chronically ill uremic patient. All metabolized citrate rapidly, the normals excreting in the urine 4.5% of the infused citrate and the uremic 1%. In one chronically ill uremic patient there was a marked peripheral arteriovenous difference. These data suggest that the peripheral arterial citrate concentration in uremic patients is elevated, that it is consistently higher than the peripheral venous concentration, that there is marked utilization of citrate by the peripheral tissues (tissues existing between the peripheral artery and the peripheral vein), that lack of excretion of citrate by the uremic patient does not explain the elevated serum citrate concentration, and that overproduction of citrate by the liver is responsible for the hypercitricemia observed in uremia.