[Metabolism of cGMP with K+ concentration increase in the medium causing depolarization of cortical cell membranes in normal and irradiated rats].

An increase in the K+ concentration in the medium to 60 mM which causes depolarization of cell membranes in the rat cerebral cortex is studied for its effect on the cGMP level, guanylate cyclase and cGMP phosphodiesterase activities in norm and one hour after X-ray irradiation. The cGMP content and guanylate cyclase activity in normal rats and 1 min after depolarization are shown to increase with the external K+ concentration. One hour after irradiation the activity of enzymes under examination is three times as high. The character of changes in the cGMP content caused by a rise of the external KCP concentration is mainly determined by variations in the guanylate cyclase activity under these conditions.