Human Red Cell Content of Cyclic Nucleotides and Cations upon β-adrenergic Blockade

The content of cyclic nucleotides (cAMP, cGMP) and Mg2+, Zn2+,Na+ and K+ was determined in human erythrocytes and after beta-adrenergic blockade in healthy individuals. The figures for cAMP and cGMP were 4.20 and 3.36 nmoles/ l intracellular volume, respectively. Only slight effects on the cyclic nucleotide content as well as on cation content were seen upon beta-blockade in the erythrocytes. It is concluded that the single determination of red cell cAMP is not a sufficient indicator of beta-adrenergic blockade. The determination of cAMP in combination with cGMP, Zn2+ and Na+ might reflect a beta-adrenergic blockade.