Partial inhibition by lithium of the epinephrine-stimulated rise in plasma cyclic GMP in humans.

Lithium-treated and drug-free individuals were each given 0.5 mg epinephrine subcutaneously and blood samples withdrawn for measurement of plasma cyclic AMP and cyclic GMP. The rise in plasma cyclic GMP in response to epinephrine was found to be partially inhibited by lithium treatment, and previous reports of lithium inhibition of the plasma cyclic AMP rise were replicated. Effects of lithium on cyclic AMP and cyclic GMP may relate to lithium's biphasic efficacy in depression and mania.