Changes in the TBARs content and superoxide dismutase, catalase and glutathione peroxidase activities in the lymphoid organs and skeletal muscles of adrenodemedullated rats

Thiobarbituric acid reactant substances (TBARs) content, and the activities of glucose-6-phosphate dehydrogenase (G6PDh), citrate synthase (CS), Cu/Zn- and Mn-superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) were measured in the lymphoid organs (thymus, spleen, and mesenteric lymph nodes (MLN)) and skeletal muscles (gastrocnemius and soleus) of adrenodemedullated (ADM) rats. The results were compared with those obtained for sham-operated rats. TBARs content was reduced by adrenodemedullation in the lymphoid organs (MLN (28 percent), thymus (40 percent) and spleen (42 percent)) and gastrocnemius muscle (67 percent). G6PDh activity was enhanced in the MLN (69 percent) and reduced in the spleen (28 percent) and soleus muscle (75 percent). CS activity was reduced in all tissues (MLN (75 percent), spleen (71 percent), gastrocnemius (61 percent) and soleus (43 percent)), except in the thymus which displayed an increment of 56 percent. Cu/Zn-SOD activity was increased in the MLN (126 percent), thymus (223 percent), spleen (80 percent) and gastrocnemius muscle (360 percent) and was reduced in the soleus muscle (31 percent). Mn-SOD activity was decreased in the MLN (67 percent) and spleen (26 percent) and increased in the thymus (142 percent), whereas catalase activity was reduced in the MLN (76 percent), thymus (54 percent) and soleus muscle (47 percent). It is particularly noteworthy that in ADM rats the activity of glutathione peroxidase was not detectable by the method used. These data are consistent with the possibility that epinephrine might play a role in the oxidative stress of the lymphoid organs. Whether this fact represents an important mechanism for the establishment of impaired immune function during stress remains to be elucidated

Fatty acid oxidation in lymphocytes from Walker 256 tumor-bearing rats

The oxidation of fatty acids in lymphocytes from the mesenteric lymph nodes of Walker 256 carcinosarcoma-bearing rats (TB) was studied, as well as the activity of the mitochondrial long-chain fatty acid transport system. Two-month old Wistar rats were subcutaneously implanted with 10(7) cells and after 2 weeks the tumor mass was 15-20 per cent of the carcass weight. The activity of camitine palmitoyltransferase (CPT) II was demonstrable in the lymphocytes of the TB group (8.2 ñ 5.6 nmol/min per mg mitochondria protein for 15 rats) and was not detected in the control, while that of CPT I was only slightly increased in the former. Similar rates of [1-14C]-palmitate decarboxylation were found for TB and control rat lymphocytes. However, when the rate of decarboxylation of [1-14C]-paimitate present in the intracellular pool of lipids was investigated in cultured lymphocytes, the cells of TB rats exhibited rates 17-fold higher than those of control animals in the presence of fetal calf serum (FCS). Decarboxylation in the presence of TB rat serum was 178-fold higher than obtained with normal rat serum, and 1.4-fold compared to FCS. These results suggest that, during cachexia, lymphocytes preferably oxidize intracellular lipids, and that this capacity is greatly enhanced by factors circulating in the serum of tumor-bearing rats.

Effect of a polyunsaturated fatty acid-rich diet on macrophage and lymphocyte metabolism of diabetic rats

Diabetic subjects present high susceptibility to infections but the mechanisms involved are not fully known. Macrophages and lymphocytes utilize glucose and glutamine at high rates and these metabolites are important for the function of these cells. The present study examines the activities of key metabolic enzymes in macrophages and lymphocytes obtained from alloxan-diabetic Wistar rats (10 weeks old, 7 rats each group). Since the enteral diet was enriched with omega-6 polyunsaturated fatty acids (PUFA), the effect of these fatty acids was also investigated in the same animals. Diabetes caused a marked decrease of hexokinase activity (48 per cent ; 274.23 +/- 18.43 vs 143.29 +/- 10.35 units for control vs diabetic rats) in macrophages and of citrate synthase and glucose-6-phosphate dehydrogenase activities (70 per cent ; 321.76 +/- 9.18 vs 96.25 +/- 5.43 units for citrate synthase and 89.43 +/- 2.33 vs 23.13 +/- 1.09 units for G6PDh for control vs diabetic rats) in mesenteric lymph node lymphocytes. A PUFA-rich diet given for 6 weeks enhanced hexokinase activities by 30 per cent (274.23 +/- 18.43 vs 342.48 +/- 15.39, balanced vs PUFA-rich diets for normal and 143.29 +/- 10.35 vs 189.67 +/- 9.57 for diabetic rats) and reduced citrate synthase activities by 43 per cent (30.31 +/- 1.73 vs 17.42 +/- 0.95, balanced vs PUFA-rich diets for normal and 29.34 +/- 1.23 vs 16.73 +/- 1.02 for diabetic rats) in macrophages, and reduced (< 50 per cent ; 59.67 +/- 3.45 vs 48.87 +/- 3.37 for hexokinase and 321.76 +/- 2.33 vs 161.66 +/- 9.97 for citrate synthase, balanced vs PUFA-rich diets) the activities of both enzymes in lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)