Postnatal lead exposure animal studies

In contrast to the animal studies for prenatal exposure, animal studies for postnatal exposure report effects at blood lead levels similar to those associated with effects in humans. 

Impairment of heme-biosynthesis as well as neurotoxic lead effects, especially effects on the central nervous system (C.N.S.)/ are considered to be early signs of incipient damage due to lead. Neurobehav-ioral studies in animals show that, for example, deficit of learning-performance already occurs at blood-lead concentrations between 20 and 30 yg/dl in rats, if the exposure is not only postnatal, but pre- and neonatal as well, i.e. when it takes place during the period of brain maturation, also (Winneke et al., 1977 1982a). 

The in vivo effect of chronic lead exposure on the acquisition of neural cells in the developing rat brain was assessed by measuring the rate of pH]thymidine incorporation into DNA. Wistar rats were used throughout the entire study and were maintained at 20°C and in a 12 h light/dark cycle. The animals had ad libitum access to food and water at all times. The pups were exposed to lead from their time of conception to the required postnatal period via their dams, who had ad libitum access to drinking water containing 400 mg PbCl2/l. Food and water intake was constantly monitored over exposure periods, and no difference in food and water intake was observed between control and lead-exposed animals. 

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