Effects of methylmercuric chloride in the presence of cyclic AMP-stimulating agents on glioma and neuroblastoma cells in culture.

The intracellular level of adenosine 3′, 5′-cyclic monophosphate (cyclic AMP) increased in rat glioma (C-6) and mouse neuroblastoma cells (NBP₂) after treatment with methylmercuric chloride (CH₃HgCl). The effects of CH₃HgCl in the presence of cyclic AMP-stimulating agents on glioma cells were in part different from those on NB cells. CH₃HgCl increased prostaglandin E₁ (PGE₁)-induced growth inhibition (due to reduction in cell division and cell death) in glioma and NB cells. CH₃HgCl did not reduce PGE₁-induced formation of cytoplasmic processes in glioma cells except at a higher PGE₁ concentration, but it did decrease PGE₁-induced neurite formation in NB cells. The inhibitors of cyclic nucleotide phosphodiesterase completely prevented the cytotoxic effect of CH₃HgCl on glioma cells, but they markedly enhanced the growth inhibitory effect of CH₃HgCl on NB cells.