Exploring a partially enclosed space by lead-exposed female rhesus monkeys

Beginning on Day 8 postpartum, lead acetate was administered to female rhes us monkeys (n =48). Their blood lead levels rose to 35-40 mug/dl (the level maintained for the duration of the study period) by 12 weeks of age. Weekl y, these lead-exposed monkeys and their controls (n = 23) were placed in a partially enclosed space from the second postnatal week until they escaped three times or were 26 weeks old. The lead-exposed monkeys exhibited more f ear, were more likely to be agitated, and climbed more frequently during th e first testing session. In subsequent sessions, they more frequently explo red the periphery of the test area than the controls. The lead-exposed monk eys also tended to escape sooner although that trend did not consistently r each the .05 level of significance. The increased activity and agitation of the lead-exposed monkeys is suggestive of deficits reported in human child ren with high blood lead levels. (C) 2001 Elsevier Science Inc. All rights reserved.