ORGAN DISTRIBUTION OF 65ZN IN EHRLICH ASCITES CANCER-BEARING MICE

Abstract

Organ distribution of 65Zn injected i.p. or s.c. into Ehrlich ascites cancer-bearing mice was examined with the following results.1) Distribution of 65Zn injected i.p. was examined as a function of time (1-24 hr). 65Zn was found mainly in ascites cancer cells reaching a maximum (26%) 6 hr after the injection and its concentration was gradually decreased thereafter. Radioactivity of 65Zn in liver, kidney, pancreas and spleen were less than that in cancer cells. Disappearance of the radioactivity contained in cancer cells was very little after washing.2) Subcellular distribution pattern of 65Zn in ascites cancer cells was examined extending from 1 to 24 hr after i.p. injection. The amount of 65Zn in supernatant fraction was highest followed by nuclear, microsomal and mitochondrial fractions in the descending order and the above distribution pattern was same at any times.3) Radioactivity of 65Zn administered s.c. into cancer-bearing mice was significantly increased in the liver and decreased in pancreas and blood with no changes in the kidney and spleen compared with that in normal mice. After the i.p. injection of 65Zn into cancer-bearing mice, 66% of total radioactivity was found in ascites and 65Zn concentration in the liver, kidney, pancreas, spleen and blood were less than that in normal mice.4) When the radioactivity of 65Zn injected i.p. or s.c. in the subcellular fractions of liver and cancer cells are expressed per mg protein, the highest concentration of 65Zn in the liver was found in the supernatant fraction followed by microsomal, nuclear and mitochondrial fractions in the decending order. These distribution pattern of 65Zn was equal with that of cancer cells.5) 65Zn in the liver and cancer cells binds loosely with protein. After the treatment of each subcellular fractions obtained from liver and cancer cells with (NH4) 2SO4 (70% saturation) and trichloroacetic acid (10% in final), most of 65Zn was distributed in supernatant excepting the liver nuclear fraction in which most of radioactivity exists in precipitate by (NH4) 2SO4.6) Subcellular distribution of 65Zn in mammary carcinoma was examined 24 hr after the s. c. injection. 65Zn concentration is equal in nuclear and supernatnat fractions followed by microsomal and mitochondrial fractions in the descending order. The distribution pattern of 65Zn in nuclear fraction was different from that in the liver.