Toxicological Studies of Tritiated Thymidine

Abstract

Factors influencing the expression of radiotoxicity of tritiated thymidine in the mouse were studied, and parameters for toxicity measurement were evaluated. Uptake and retention of activity were found to be only partially related to total dose given at a single time. Dividing of doses into serial parts increased uptake and retention, whereas increasing the speciflc activity of TdH/sup 3/ used or increasing the age of the animal decreased uptake and retention. Several parameters for measuring radiotoxicity of TdH/sup 3/ were studied, but cytological damage to testis was found most consistently and proportionately related to exposure. It is suggested that toxicity of tritiated thymidine is best related to uptake and retention rather than to administered intraperitoneal dose, and that factors influencing uptake and retention may play an important role in expressed radiotoxicity. (auth)