[Radiobiological characteristics of tritium labeled lysine]

Experiments on mice and rats injected with tritium-labeled lysine have revealed that one day after injection about 80% of the label was retained in organs and tissues as tissue-bound tritium. Retention curves for tritium in the body were decomposed into two exponentials. The biological half-lives of tritium-labeled lysine in various tissues exceed half-lives of other tritiated amino acids and of tritiated water. The average dose in different tissues following injection of tritiated lysine exceeds that from equal quantity of tritium oxide (THO) by 1,5-8 times. Contribution of the tissue-bound tritium in dose is about 90%. Radiobiological experiments showed strong genetic and cytotoxic effects in male mice after injection of tritium-labeled lysine.