Metabolism of glucose, glutamine and pyruvate in lymphocytes from Walker 256 tumor bearing rats

RESUMO

This study examined the effect of Walker 256 tumor growth in vivo on the metabolism of glucose, glutamine and pyruvate in lymphocytes. A comparison between the metabolism of Walker 256 tumor cells obtained in vivo with that of lymphocytes was also carried out. Lymphocytes and tumor cells were isolated and incubated for 1 h for the following measurements lactate production from glucose (5.6 mM) and pyruvate (3 mM), glutamate and aspartate formation from glutamine (3 mM) and decarboxylation of [U-14C]-glucose, [U-14C]-glutamine, [1-14C]-pyruvate and [3-14C]-pyruvate. The presence of the tumor increased lactate production (2.7-fold from glucose and 2-fold from pyruvate), decarboxylation of [U-14C]-glucose (3.7-fold) and [1-14C]-pyruvate (4.4-fold) and the formation of aspartate (6.3-fold) and glutamate (4.6-fold) from glutamine. The conversion of glucose to lactate and CO2 was higher in tumor cells as compared to lymphocytes. Tumor cells also showed a higher production of glutamate and an 8-fold increased decarboxylation rate of [U-14C]-glutamine in tumor cells, which was more active than that of lymphocytes even from tumor-bearing rats. Tumor growth stimulated glucose and glutamine metabolism in lymphocytes; however, the importance of this fact for the function of these cells remains to be elucidated