Abstract
The metabolic pathway for the synthesis of guanidinosuccinic acid was studied in the rat. Labeled guanidinosuccinic acid was isolated from the urine of animals given L-[guanidino-14C]arginine intraperitoneally but did not appear in the urine after administration of D,L-[guanidino-14C]canavanine. Radioactive arginine and nonradioactive aspartic acid and arginine were infused in the isolated, perfused rat liver. After 20 min, small amounts of both labeled and unlabeled guanidinosuccinic acid and large amounts of urea were detected in radiochromatograms of the perfusate. These results support the theory that guanidinosuccinic acid is formed in the liver from transamidination of arginine to aspartic acid.