Water content in cultured mammalian cells for dosimetry of beta-rays from tritiated water

One of the critical factors for dosimetry of beta-rays from tritiated water is the water content within the cell. We estimated the cellular water concentration in cultured mammalian cells by measuring accurately the fraction of the extracellular water in the cell sample with [14C]inulin. The net water content (ml.g-1) after correcting for the extra-cellular water fraction was 0.858 for HeLa (human), 0.833 for JTC12P3 (monkey), 0.829 for NRK (rat), 0.843 for C3H10T1/2 (mouse) and 0.846 for L5178Y (mouse) cells. The mean water content (+/- S.E.M.) in these 5 lines of cultured mammalian cells was 0.842 +/- 0.005.