Absorption of Caesium 137 from the Gastro-intestinal Tract of the Rat

SummaryThe absorption of 137Cs from the gastro-intestinal tract of the rat has been studied in vivo. The data suggest that the presence or absence of food in the digestive tract affects the movement of 137Cs through the digestive tract and the rate of absorption. 137Cs was absorbed rapidly from the gastro-intestinal tract of the rat. Absorption occurred from all anatomical areas investigated, the small intestine being the most important site of absorption. The stomach and caecum absorbed only minute quantities. Using Dowex 50, total endogenous secretion was estimated at approximately 24·5 per cent of the initial dose, as measured over the first hour after injection. Taking endogenous secretion into consideration, the total amount absorbed at the end of one hour was 98·2 per cent of the initial dose.