DECREASED UPTAKE OF C-14-LABELED DICARBOXYLIC AMINO-ACIDS IN RAPIDLY GROWING HEPATOMAS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (11) , 4053-4058
Abstract
In contrast to the increased uptake of amino acids in many neoplastic cells, a decrease in the net uptake of [14C]aspartate and [14C]glutamate was found in rapidly growing hepatomas relative to rat host liver. When measured 10 min after s.c. injection, the radioactivity from 14C-labeled dicarboxylic amino acids was greater in liver than in all other tissues examined (blood, skeletal muscle, heart, spleen, lung and brain) except kidney, where there was an .apprx. 2-fold greater uptake of aspartate and 10-fold greater uptake of glutamate. Mean uptakes in the rapidly growing Morris hepatomas 7288CTC and 7777 were 9-26% of corresponding values for the host livers. Comparison with uptake of 3H2O indicated that these low values were not solely due to differences in circulation. Decreased uptake was not accompanied by equivalent decreases in the concentration of aspartate and glutamate in the tumors. There were small changes in the net uptake of these amino acids in the slowly growing hepatoma 7787 and no significant differences in regenerating liver and hepatoma 5123C, a tumor intermediate growth rate. The net uptake of [14C]arginine and [14C]lysine in the hepatomas was similar to that in host livers, except for a 250% increase in uptake of [14C]lysine in hepatomas 5123C. A decreased uptake of the magnitude seen with dicarboxylic amino acids in rapidly growing hepatomas was not observed with other amino acids.