Aminoacyl-tRNA synthetases in liver, spleen and small intestine of aged leukemic and aged normal mice.

The specific activities of 17 aminoacyl-tRNA synthetases in liver, lung, heart, spleen, kidney and small intestine of old female normal and leukemic (reticulum-cell sarcoma, type A) mice have been monitored. No difference appears for lung, heart and kidney; small increases with varying particular changes for liver and marked increases in spleen and small intestine of the tumor bearing mice have been found, following a similar pattern. This finding suggests a coordinated adaptation to modulation of the requirements of protein synthesis imposed by histiocytic sarcoma.