Antagonistic effect of zinc on increased urine δ-aminolevulinic acid excretion in lead-intoxicated rats

Abstract Urine δ-aminolevulinic acid (ALAU) excretion has previously been reported as being closely correlated with the clinical picture of lead poisoning. In the present investigation, rats were administered either zinc or lead or both. Zinc administration resulted in the reduction to near normal levels of ALAU excretion in lead-intoxicated rats. This effect occurred in the absence of any significant reduction in blood lead levels or any alleviation of the anemia of lead toxicity. The observations place considerable doubt on the validity of using ALAU screening tests as a means of determining lead exposure.