Negative relationships between erythrocyte Ca-pump activity and lead levels in mothers and newborns

Lead poisoning induces hematological, gastrointestinal and neurological dys functions. One of the potential mechanisms is the inhibition of calcium-pum p (Ca-pump), a transport protein. We investigated the effects of an environ mental low lead exposure on Ca-pump activity in 247 mothers and their newbo rns. Maternal and cord blood, and newborn and mother hair, were sampled at delivery. Geometric means for mother and cord blood lead (Pb-B), and for mo ther and newborn hair lead (Pb-H), were 6.3 and 4.8 mug/dl, and 1.7 and 1.1 mug/g. Means for mother and cord basal Ca-pump activities were 2442 and 26 75 nM/mg/hr. Mother enzymatic activity was negatively related to her Pb-B a nd Pb-H and to the cord Pb-B and newborn Pb-H levels. Newborn enzymatic act ivity was negatively related to his P-H level only. Adjustment for gestatio nal age, child's sex, mother's age at delivery, alcohol, coffee and tea con sumption, and smoking habits during pregnancy did not modify these relation ships. Our findings support the hypothesis that lead toxicity could be in p art mediated by a reduction of Ca-pump activity. This effect could be obser ved at low environmental exposure, in mothers and newborns. (C) 2000 Elsevi er Science Inc. All rights reserved.