The purpose of work was study of contents of creatine metabolism precursors: arginine, glycine and guanidine acetate in tissues of 1-month-old posterity and adult rats. It is established, that creatine synthesis precursors concentration in intact 1-month-old posterity is considerably lower than in adult animals, and the contents of investigated amino acids in the blood is higher and they are excreted in a greater amount in comparison with intact adults. It is an evidence that functionaly creatine-forming system of 1-month-old posterity is much more weak, than adults’, and high concentration of arginine, glycine and guanidine acetate in the blood, probably, associated with intensifying of the biosynthetic processes in young animals.
