Effects of WR 2721 on cyclic nucleotide levels and lysosomal enzyme activities.

The radioprotectant WR 2721 administered intraperitoneally to rats at 30--40 min before exposure to 1000 rad of 60Co caused a reduction in spleen lysosomal enzyme activity and fluctuations in cyclic nucleotide levels. Liver and spleen cAMP levels from drug-treated animals were higher at 3--6 hr postirradiation whereas spleen cGMP levels were lower at 1--4 hr postirradiation than irradiated controls not given the radioprotectant. At 3 days after radiation exposure, spleen cyclic nucleotide levels and lysosomal enzyme activities in rats given WR 2721 were closer to the level of nonirradiated control rats than of irradiated rats receiving saline.