TRITIUM RADIOBIOLOGICAL EFFECTS IN MAMMALS - REVIEW OF EXPERIMENTS OFTHE LAST DECADE IN RUSSIA

This review briefly describes techniques and basic results of experime ntal investigations in mice and rats on metabolism, dosimetry, and rad iobiological effects of tritium oxide and some tritiated biogenic comp ounds (glucose, amino acids, and nucleosides) during the last 10 to 15 years in Russia. The content of water in tissue cells of mammals is s hown to be 15 to 40% less than in whole tissue. The kinetics of tritiu m incorporation from oxide (HTO) and its retention in DNA of hemopoiet ic tissues were studied. The contribution of bound tritium to dose str ongly depends on the chemical form of tritium and reaches 90% when lab eled L-lysine is injected. Specific features of the action of HTO on h emopoietic tissue were investigated in tests of damage and repair of D NA, induction of chromosome aberrations in cells, content of nucleic a cids, kinetics of cell populations, immunity parameters, carcinogenesi s, decrease of life span, induction of dominant lethal mutations in ge rm cells in male mice, and reciprocal translocations in mouse spermato gonia. According to these tests, the radiobiological effects of tritiu m beta radiation in the form of oxide is 2 to 6 times higher than for gamma radiation of Cs-137. The frequency of dominant lethal mutations induced by labeled lysine, thymidine, and deoxycytidine is 3 to 12 tim es higher than those induced by equal HTO activity. The results of the se investigations are used to standardize HTO and the various biogenic compounds of tritium, improve techniques of indirect dosimetry, provi de medical aid to personnel, and estimate population risk.