IN VITRO PYRROLE AND PORPHYRIN SYNTHESIS IN LEAD POISONING AND IRON DEFICIENCY*

Abstract

Activity of amino-levulinic acid dehydrase (ALAD) was significantly decreased in erythrocytes of patients with plumbism. ALAD activity in Fe deficient erythrocytes was not significantly different from normal. Preactivation of incubation mixtures with glutathione (GSH) greatly increased ALAD activity in the Pb poisoned erythrocyte but had no effect on normal RBC. This suggests that Pb inactivates SH groups on which ALAD is dependent; an effect which may be reversed in the presence of an SH donator such as GSH. Uro and coproporphyrin synthesis from aminolevulinic acid(ALA) was reduced in plumbism. This deficit was not altered by preincubation with GSH. This suggests a defect in porphyrin synthesis after the formation of porphobilinogen. Uroporphyrin synthesis from ALA was significantly diminished in the Fe deficient erythrocyte.