Experimental lead neuropathy: Inorganic lead inhibits proliferation but not differentiation of Schwann cells

Schwann cells were prepared from the sciatic nerves of newborn rats and cultured in a monolayer. Addition of lead acetate at concentrations between 0.4 and 10.0 μg/ml, levels comparable to those occurring in neural tissues and physiological fluids of lead-intoxicated rats, diminished both the baseline rate of proliferation of the Schwann cells and their response to the mitogens, axolemmal fragments, glial growth factor, and the adenosine 3':5'-cyclic monophosphate (cAMP) analogues 8-bromo-cAMP and dibutyryl-cAMP. This demonstrates a direct toxic effect of inorganic lead on Schwann cells. Lead acetate in this concentration range did not, however, inhibit the cAMP analogue-induced appearance of the 'myelin marker' lipid galactocerebroside on the surfaces of the cultured Schwann cells.