Stimulation of adenosine 3',5'-monophosphate formation in mononuclear leukocytes by toad venoms.

The content of adenosine 3',5'-monophosphate in human mononuclear leukocytes was enhanced 3-5-times by venoms obtained from African toad (Bufo africanus), American toad (Bufo americanus), Colorado river toad (Bufo arenarum) and Marine toad (Bufo marinus) at 25 micrograms/ml for 5 min of incubation at 37 degrees C. The maximum stimulation was observed after 1-5 min of incubation. The half-maximal stimulation was observed at 0.1 micrograms/ml venom obtained from Colorado river toad (Bufo arenarum). The increased content of adenosine 3',5'-monophosphate in the mononuclear leukocytes persisted without significant change for at least 30 min of incubation at 37 degrees C.