Biochem/physiol Actions Membrane permeable cAMP analog. Used as a selective activator of cAMP dependent protein kinase (PKA). Inhibits cGMP-dependent phosphodiesterase and, at higher concentrations, inhibits cAMP-dependent phosphodiesterase. Inhibits phosphoinositide hydrolysis and secretion stimulated by n-formyl-Met-Leu-Phe but not platelet-activating factor in leukocytes. Renders HL-60 cells more resistant to NO-induced DNA damage.