Cytochemical localization of adenyl cyclase in isoproterenol stimulated hepatoma ascites cells.

Although adenyl cyclase (AC) has been reported for many mammalian cell types its presence in transformed cells is controversial since AC activity is present in some tumors but absent in others. Thus Chang hepatoma ascites cells were investigated to determine if AC could be localized cytochemically in this cell type. Using a variation of the method of Reik et al. (1970), AC was localized at the surface of the bile canaliculi and intercellular spaces of frozen liver sections of a normal rat. By contrast AC could be localized on the surface of hepatoma ascites cells only after preincubation treatment of unfixed cells with isoproterenol. The specificity of the reaction was confirmed when untreated ascites cells or cells incubated in AC media without the substrate were free of any reaction product. The results of this study indicate that AC activity is present in hepatoma ascites cells but that it can only be demonstrated after isoproterenol stimulation.