标题：DIFFERENCE BETWEEN MAGNESIUM AND MANGANESE IONS IN MODIFICATION OF EFFECT OF CATECHOLAMINE ON ADENYLATE CYCLASE SYSTEM IN EHRLICH ASCITES TUMOR CELLS
摘要：Involvement of divalent cations was examined in the activation of catecholaminesensitive adenylate cyclase in Ehrlich ascites tumor cells. In the presence of various concentrations of either Mg2+ or Mn2+, both basal and norepinephrine-stimulated adenylate cyclase activities were measured. Both activities were gradually increased with the increase in Mg2+ concentration. On the other hand, with Mn2+, both activities were maximum at the low (2.5mM) concentration, and decreased at the higher concentrations, the decrease being marked in the norepinephrine-stimulated activity. Similar difference between the two divalent cations was also observed in the effect on the binding of the β-adrenergic ligand to the membrane receptor.
