DIETARY CALCIUM AND LEAD INTERACT TO MODIFY MATERNAL BLOOD-PRESSURE, ERYTHROPOIESIS, AND FETAL AND NEONATAL GROWTH IN RATS DURING PREGNANCYAND LACTATION

We studied the effects of dietary calcium and lead exposure on lead to xicity, fetal and neonatal growth, erythropoiesis and blood pressure d uring pregnancy and lactation in rats. Pregnant Sprague-Dawley rats (n = 43) were randomly assigned to one of six treatment groups of 7-8 ra ts each. Half of the rats were fed diets of low (0.1%), normal (0.5%) or high (2.5%) calcium as calcium carbonate and exposed to 250 mg/L of lead in their drinking water for the duration of the pregnancy and fo r 1 wk of lactation. Three control groups were fed the same diets with out lead exposure. Pups were studied at 1 d and 1 wk of age. Maternal and fetal blood and organ samples from the groups fed the low calcium diet had the highest lead concentrations, whereas the lowest lead conc entrations were found in the groups fed the high calcium diet. Dam and pup hemoglobin concentrations, hematocrits, and body weights and leng ths were reduced by lead exposure and by the high calcium diet. The la tter also reduced organ iron concentrations and prevented lead-induced increases in free erythrocyte protoporphyrin. Dam systolic blood pres sures during the third trimester of gestation were significantly highe r in rats exposed to lead and fed the low calcium diet than in rats in the other five treatment groups. The results demonstrate that dietary calcium and lead exposure interact in rats to influence maternal bloo d pressure, erythropoiesis, and fetal and neonatal growth during pregn ancy and lactation.