Effect of pertussis toxin on hormonal responsiveness of rat hepatocytes

Abstract

The ureogenic action of epinephrine in hepatocytes from normal adult rats is mediated through activation of α₁‐adrenoceptors. β‐Adrenoceptors in addition to α₁‐adrenoceptors, became involved in mediating this effect in cells from animals treated with pertussis toxin. The accumulation of cyclic‐AMP in response to epinephrine or isoproterenol was markedly increased in hepatocytes from pertussis‐treated rats as compared to that observed in control cells. The accumulation of cyclic‐AMP due to glucagon was also increased. It is suggested that pertussis toxin may release a constraint on adenylate cyclase activity by blocking the inhibitory coupling mechanism (N _i) or some other entity involved in the regulation of the activity of this enzyme.