COMPARISON OF THE ACTIVITY VALUES OF ERYTHROCYTE δ-AMINOLEVULINIC ACID DEHYDRATASE, AS MEASURED BY TWO DIFFERENT METHODS

Abstract

Erythrocyte δ-aminolevulinic acid dehydratase (ALA-D) activity in blood speci-mens from normal and lead-exposed workers was simultaneously determined accord-ing to two methods with different principle. In one method, erythrocyte ALA-D activity is calculated from the amount of porphobilinogen (PBG) formed by enzyme assay. In the other method, the ALA-D activity is calculated from the amount of substrate δ-aminolevulinic acid (ALA) consumed during incubation.
The value of erythrocyte ALA-D activity (micromols ALA/min/liter RBC) ob-tained from the amount of ALA consumed was more nearly accurate than the value (micromols PBG/min/liter RBC) obtained from information on the amount of PBG formed. In addition, in the workers occupationally exposed to lead, the blood lead levels tended to more inversely correlate with the value of erythrocyte ALA-D activity calculated from ALA consumed than that from PBG formed.