Some effects of irradiation of mice in utero with tritiated compounds

Mice have been exposed continuously, in utero, to tritiated water (via the maternal drinking water) or to tritiated thymidine (infused continuously into the mother). In both cases the patterns of labeling and subsequent loss of tritium over an extended period have been studied. The technique of infusion in unrestrained mice and its application in the production of fully tritium-labeled offspring is described in some detail. These fully labeled mice are being used to study a number of early and late effects, in particular, gonad cell effects and carcinogenesis, following this form of internal irradiation. Some preliminary results are presented. Similar results produced a homogeneous irradiation from tritiated water are also reported.