Creatine formation in liver and in kidney

We reported recently (1) the formation of creatine from glycocyamine by rat liver slices; and that 40 to 50 per cent more creatine was formed when methionine was added with the glycocyamine to the Ringer's solution in which the slices were immersed. Among some thirty odd amino acids, methylated amines, a methylated purine, and betaine only methionine gave this increased rate of methylation. The rate of creatine formation under these conditions is sufficient, if it is of the same order of magnitude in vivo, to make good the entire loss as urinary creatinine.