Level of newly synthesized cyclic AMP in the isolated rat kidney cells and its changes by vasopressin.

phosphate (cyclic AMP) newly synthesized ruring in vitro incubation of the isolated rat kidney cells with adenine-8-14C. By combined use of the BaSO4 treatment and the onedimensional ascending cellulose thin-layer chromatography with stepwise development by two solvents, newly formed or labeled cyclic AMP (14C-cyclic AMP) could completely be separated from the related radioactive metabolites in the cells. Effect of lysine-vasopressin on the isolated rat kidney cells was studied by using the radioassay method. It was shown that (1) in the presence of theophylline, vasopressin increased 14C-cyclic AMP level, and (2) the stimulative effect was specific to vasopressin. Moreover, (3) vasopressin was shown to increase 14C-cyclic AMP level markedly in the medium but little in the cells. It was thus indicated that over-all synthesis of cyclic AMP in the rat kidney cells and consequential excretion of the newly synthesized cyclic AMP into the medium were enhanced by vasopressin.