[Microassay for blood adenosine deaminase: study of the role of the enzyme in the ammoniagenesis of the blood sample].

A microassay for adenosine deaminase is elaborated. It is based on the colorimetric measurement of small amounts of ammonia raised during adenosine deamination and separated by continuous flow dialysis. The analytical qualities of the microassay are reported. The enzymic activity concentration in whole arterial blood of 30 control subjects is 2.54 +/- 1,68 micro katal/l (mean +/- 2ET). It is slightly lower in venous blood. The values are higher in man than in women. 92 p. cent of the enzymic activity of whole blood are due to the erythrocytes. The distribution of the arterial enzymic activity concentrations is not significantly different in a group of 85 cirrhotic patients when compared to the control group. No tight correlation can be found between blood adenosine deaminase concentrations and either blood ammonia nor shed blood ammoniagenesis. Inhibitors of adenosine deaminase have little effects on the in vitro ammoniagenesis.