The effects of lead on delta-aminolevulinic acid dehydratase activity of the erythrocytes and tissue in pregnant and nonpregnant rats. II. Administration of lead at a low concentration.

Abstract

Hematological and biochemical changes were studied in pregnant and nonpregnant rats that had been given drinking water containing 5 ppm of lead for 23 days. Pregnant and nonpregnant rats administered distilled water served as controls. The red blood cell count, packed cell volume and hemoglobin con-centration were significantly decreased in the pregnant rats, but there were no significant differences in these values between the control and lead-treated groups. Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was significantly reduced in the lead-treated pregnant rats. There was no significant difference in liver AL AD activity between the control and the lead-treated groups, whether pregnant or not. The concentration of blood lead (Pb) ranged from one to three, μg/100 ml in the nonpregnant rats and from three to eight μg/100 ml in the pre-gnant rats. A statistically significant negative correlation between erythrocyte AL AD activity and the blood Pb level was observed only in the pregnant rats. These results indicate that the response level of lead on erythrocyte AL AD activity may be much lower than that on changes in the concentration of blood Pb during pregnancy and empasized that special attention should be paid to avoiding exposure of expectant mothers to lead even at a low level.