Acute effects of orally administered sodium arsenate on heme biosynthetic enzymes in the tissues of three strains of mice

Sodium arsenate (Na2HASO4· 7H2O, As(V)) was administered to three genetically different strains of mice, ICR, C57BL/6J and DBA/2J, in a single oral dose of 54 mg kg−1 body weight. The effects on the activities of heme biosynthetic enzymes in the spleen, liver, kidney and peripheral blood were investigated. The activities of δ-aminolevulinate synthase (ALAS, EC 2.3.1.37), catalyzing the first reaction in the heme biosynthetic pathway and the rate-limiting enzyme for heme synthesis, δ-aminolevuilinate dehydratase (ALAD, EC 4.2.1.24) and porphobilinogen de-­aminase (PBGD, EC 4.3.1.8) in the spleens of the ICR strain, were remarkably reduced to 51%, 32% and 42%, respectively, in comparison with each mean value of the control group. In contrast, these activities were significantly increased in the livers of the C57BL/6J strain, and a similar trend was observed in the DBA/2J strain. In the kidneys, the ALAD activity was significantly reduced in the ICR strain, but no significant differences in the other two strains were found. These results suggest that the influence of As(V) on the activity of heme biosynthetic enzymes is most potently manifested in the spleen tissue of the ICR strain. Copyright­© 1999 John Wiley & Sons, Ltd.