Tracer Studies on the Metabolism of the Gardner Lymphosarcoma

Summary

It has been shown that the incorporation of four amino acids into the protein of the Gardner lymphosarcoma cells is markedly stimulated by the presence of glucose. Glycolytic inhibitors strongly suppressed the amino acid uptake.

The presence of succinate stimulated the respiration of the tumor cells, and, concomitant with this, a marked increase in the uptake of glycine and leucine and a slight increase in phenylalanine uptake into the cell protein were observed. Tricarboxylic acid cycle inhibitors suppressed oxidations and amino acid uptake.

Acetate-1-C¹⁴ was partly oxidized to CO₂ by the tumor cells and normal spleen cells. Some of the C¹⁴ from the acetate was found in the cell proteins. These processes and respiration were inhibited by fluoroacetate. Citrate was formed from acetate and oxalacetate by the tumor and normal spleen cells.

Alanine-1-C¹⁴, glycine-1-C¹⁴, and leucine-2-C¹⁴ were also partly oxidized to CO₂ by the tumor cells. The implications of these results are discussed.