“…In this regard, the importance of water for the implementation of physiological processes is extremely high, but it might vary and differ for each of its nine isotopologues: 1 H 2 16 O, 1 HD 16 O, D 2 16 O, 1 H 2 17 O, 1 HD 17 O, D 2 17 O, 1 H 2 18 O, 1 HD 18 O, D 2 18 O. Some of them, which predominantly contain lighter isotopes, can have in certain concentrations a stimulating effect on functional activity of living systems [5], other isotopologues, including mainly heavy isotopes, are able to inhibit vital processes, especially at high concentrations of deuterium [6,7], and in some cases it was observed that variation of deuterium concentration (both increasing and decreasing its content in water) can enhance the functional activity of living systems [8]. In this regard it is very important to know about the peculiar features of use of certain isotopologues of water for regulation of metabolic processes in a body, and for monitoring of the anabolism and catabolism state of biological substances in various diseases [9].…”