Uroporphyrinogen III cosynthetase in liver and blood in the Dubin-Johnson syndrome.

The activities of uroporphyrinogen III cosynthetase in blood lysates from five patients with the Dubin-Johnson syndrome (DJS) and four control subjects and in liver homogenates from four patients and four control subjects were determined. No significant difference was found in enzyme activity between the two groups in either blood lysate or liver homogenate. These results indicate that low urinary coproporphyrin III output in the DJS is not due to deficiency of uroporphyrinogen III cosynthetase in the liver and the erythropoietic system.