Incorporation of organically bound tritium into body constituent molecules

Incorporation of 3H from organic 3H into body constituent molecules through the food chain was studied. Exposure to organic 3H may result in a higher 3H incorporation into animal organs than that by exposure to HTO and to differ according to the type of food (organic form). The effect of the difference in organic forms on the in vivo behaviors of 3H was studied using leucine, glucose and thymidine labelled with 3H in rats. Compared with HTO, all of the incorporations of the 3 3H compounds into the organic components of rats 24 hours after administration were high, with great differences among the 3 compounds with respect to the level of concentration and the organ distribution. The biochemical distribution of organically bound 3H differed greatly in liver tissues depending on the chemical form of digested 3H. The excretion curve also showed differences that were rather remarkable among organs, according to the chemical form. The accumulated dose in each organ in 100 days after administration was highest for 3H-leucine at 1 μCi/g body weight, being 2 - 3-fold that of HTO. (Chiba, N.)