Effects of collagen and of aspirin on the concentration of guanosine 3':5'-cyclic monophosphate in human blood platelets: measurement by a prelabelling technique.

A method is described for isolating cyclic [(3)H]GMP from platelets preincubated with [(3)H]guanine. Collagen increased and aspirin decreased the cyclic [(3)H]GMP concentration in platelets. The results are consistent with a role for cyclic GMP in the platelet release reaction.