Distribution of copper-64 in control mice and in mice bearing ascitic Krebs tumor cells.

Three to 20 hr after an i.p. injection of 64Cu (half-life, 12.8 hr) into mice bearing Krebs ascites cells, a high amount of the radioisotope was recovered in the ascites cells themselves. In the control group, the radioisotope was mainly present in the liver. Similar amounts of 64Cu were recovered in regenerating as well as in normal liver, whereas in the liver of mice bearing ascites cells, this amount was lower by 40 to 50% regardless of the ascitic volume. Thus, the copper metabolism seems to be disturbed at the hepatic level in mice bearing ascites cells. The distribution of 64Cu was 'analyzed in DNA, RNA, and proteins from cellular lysates fractionated by CsCl gradient. There was a uniform pattern of distribution in the macromolecules from ascites cells, while 64Cu' was preferentially associated with the protein fraction from liver. Further experiments indicated that, in vivo, 64Cu was bound to the DNA of ascites cells.