Plasma cyclic 3',5'-guanosine monophosphate and cyclic 3',5'-adenosine monophosphate response to methacholine in man.

Cholinergic agents are known to induce increases in tissue and plasma levels of cyclic GMP in experimental animals. We observed that i.m. injection of methacholine, a cholinergic agent, caused significant increases in plasma cyclic GMP and cyclic AMP in man.