ASSOCIATION OF ALTERATIONS IN ENERGY-METABOLISM WITH LEAD-INDUCED DELAYS IN RAT CEREBRAL CORTICAL DEVELOPMENT

Fifteen day-old rat pups taken from dams exposed to 200 mg of lead (Pb) in drinking water were observed to have reduced synaptic densities in the cerebral cortex as determined by ethanol-phosphotungstic acid staining. Synaptic figures of animals in the Pb groups were also observed to possess a less mature synaptic profile. Cerebral cortical slices taken from pups of Pb-treated dams exhibited enhanced respiratory responses to a 3 to 30 mM increase in K+ concentration. This response was associated with a higher rate of glucose uptake by tissues of Pb-treated pups unaccompanied by a change in lactic acid output. Cerebral cortical concentrations of amino acids were not altered by Pb-treatment. Serum thyroid hormone levels were identical in 15-day old animals from the control and Pb-treated groups. These data further substantiate delayed cerebral cortical development as a result of low-level Pb exposures, and suggest that such delays may be associated with a direct effect of Pb on cerebral energy metabolism. © 1979.