[Effect of radioprotectors on cAMP-dependent protein phosphorylation]

The capacity of radioprotectors (serotonin, aminoethylisothiuronium) to stimulate in radioprotective doses cAMP-dependent protein phosphorylation of the cytozol and nuclei of the mouse liver and of the spleen cytozol was shown in vivo. Radioprotectors were incapable of modulating in vitro the activity of protein kinases and the stimulating effect of cAMP. The data presented and previous investigations suggest that the activation of cAMP-dependent phosphorylation by radioprotectors was due to the increase of intracellular cAMP concentration under the effect of radioprotectors.