Low level Pb2+ exposure affects hippocampal protein kinase Cγ gene and protein expression in rats

We examined the effect of chronic exposure to lead (Pb2+) on protein kinase C (PKC) in 50-day-old rat hippocampus. Cytosolic and membrane fractions of hippocampus from Pb2+-exposed rats showed reduced expression of PKC gamma protein. In contrast, a significant elevation of PKC gamma mRNA was observed in pyramidal and dentate granule cell layers. Protein expression of alpha, betaI, beta II and epsilon isoenzymes were unchanged in Pb2+-exposed rats, as was [H-3]phorbol 12,13 dibutyrate (PDBu) binding in tissue slices. Differences were not observed in Ca2+-dependent or -independent PKC activity, or in PKC-specific back-phosphorylation of hippocampal homogenates from Pb2+-exposed rats. Reduced subcellular levels of PKC gamma in Pb2+-exposed rats suggest that signal transduction in the hippocampus may be selectively altered and may be important in manifesting Pb2+-induced impairments of synaptic plasticity, learning and memory. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.