Inhibition of metabolic coupling by metals

Abstract

Several metals were evaluated in cell cultures for their ability to inhibit metabolic coupling, the intercellular transfer of low‐molecular‐weight metabolites by directly connecting gap junctions. To monitor inhibition of metabolic coupling, wild‐type Chinese hamster V79 cells proficient in metabolism of 6‐thioguanine (6‐TG) were co‐cultured with mutant V79 cells unable to metabolize 6‐TG to its toxic metabolite (6‐TG‐resistant cells). In the presence of 6‐TG, inhibition of metabolic coupling by the metals was manifested as increased recovery of 6‐TG‐resistant cells compared to recovery in untreated cocultures. The toxic metal compounds, arsenic(V) acid, mercu‐ry(II) chloride, lead(II) acetate, and nickel(II) chloride, significantly (p < .05) increased recovery of 6‐TG‐resistant cells at concentrations that did not alter cell survival. However, because the increased recovery observed with nickel showed no concentration dependence, its importance may be negligible. Cadmium chloride increased 6‐TG‐resistant cell recovery only at a toxic concentration, and zinc sulfate failed to increase