Effect of lead acetate on rats fed diets containing low levels of folic acid.

Nutritional factors such as deficiencies of calcium, iron, and protein alter susceptibility to the toxic effects of lead. While the suggestion has been made that vitamins may also influence lead toxicity, possible interactions have not been well documented. The present studies were performed to determine if a dietary deficiency of folic acid enhances the susceptibility to rats of the toxic effects of lead acetate. Lead exposure during the development of folate deficiency resulted in alterations in two of the parameters diagnostic of the individual conditions. Decreases in erythrocyte mean corpuscular volume (MCV) occur during lead poisoning, while increases occur during the development of folate deficiency. In the present study, significant reductions in MCV were observed in both the control + lead and in the low folate + lead groups. The increased MCV characteristic of folate deficiency was prevented by the concomitant lead exposure. Elevations in free erythrocyte protoporphyrin (FEP) levels are characteristic of lead intoxication; in contrast, FEP levels decline during folate deficiency. In the present study, FEP levels were significantly elevated only in the control + lead group. Values in the low folate + lead group were intermediate between those of the control and the control + lead groups, but did not differ significantly from those in the low folate group. The expected lead-induced elevation in FEP levels was diminished by the reduced erythropoiesis characteristic of folate deficiency.