Enhanced metabolism of glucose and glutamine in mesenteric lymph node lymphocytes from spontaneously diabetic BB rats.
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Increased energy substrate metabolism accompanies the functional activation of extrathymic immunocytes in the autoimmune BB diabetic rat, but the specific cells responsible have not been identified. To determine the possible contribution of lymphocytes to the elevated metabolism of glucose and glutamine, mesenteric lymph node cells were selected because they contain few macrophages or natural killer (NK) cells. Results from diabetic (BBd, n = 7) and non-diabetes-prone (BBn, n = 7) rats were compared with those from streptozotocin-induced diabetic (STZ-BBn, n = 6) rats. In BBd cells, all measured metabolites of glutamine (CO2, glutamate, aspartate, and NH3) in the presence of 5 mM glucose were elevated (1.5- to 2.5-fold) compared with BBn. In contrast, the only product of glucose metabolism (in the presence of 2 mM glutamine) that was increased was pyruvate (1.6-fold). All measured products of glucose metabolism were significantly lower in cells from STZ-BBn than from BBn rats. Products from glutamine did not differ. Calculated potential ATP production was greater (p < 0.05) in BBd than in BBn and STZ-BBn cells (86 +/- 5 vs. 65 +/- 2 and 53 +/- 5 nmol.2 h-1 x 10(-6) cells, respectively). However, in BBn and STZ-BBn rats, about three quarters of the cells were T (CD5+) cells and one quarter were B (MARK-1+) cells, whereas in BBd three quarters of the cells were MARK-1+.(ABSTRACT TRUNCATED AT 250 WORDS)