Subcellular distribution of some metallic cations in the early stages of liver carcinogenesis.

In the early stages of liver Carcinogenesis induced by 4-dimethylaminoazobenzene the subcellular pattern of calcium, magnesium, sodium, and potassium is sharply altered. Divalent cations decrease in the nuclear and mitochondrial fractions and in crease in the residual fraction. In the case of mitochondria, however, cations decrease proportionally to the amount of proteins and nucleoproteins in the fraction, and, there fore, the specific content in calcium and magnesium of mitochondria does not change. In the nuclear fraction, on the contrary, the quantities of proteins and nucleoproteins vary only slightly, but the level of divalent cations is strongly reduced and the specific content of calcium and magnesium in nuclei is sharply altered. Monovalent cations do not undergo profound alteration in their subcellular distribution but, at a lower degree, in general follow the pattern of divalent cations.