DIETARY FATS ALTER THE ACTIVITY AND EXPRESSION OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE IN RAT LYMPHOID-CELLS AND TISSUES

The effect of diets enriched with fat containing different fatty acids on the activity and expression of the glucose-6-phosphate dehydrogena s (EC 1.1.1.49) of mesenteric lymph nodes lymphocytes and intraperiton eal macrophages was examined. Measurements of the enzyme were also per formed using spleen, thymus and liver for comparison. The following fa t rich diets containing a variety of fatty acids were used: 1-standard chow (CC); 2- medium chain saturated fatty acids (MS)-cocconut fat-oi l, 3- long chain saturated fatty acids (LS)- cocoa butter; 4- monounsa turated fatty acids (MU)-canola oil (n-9); 5- polyunsaturated fatty ac ids (PU)- soybean oil (n-6). Of the fat-rich diets tested, MS had the least effect. The G6PDH activity of lymphocytes was reduced by all the fat-rich diets; 16% for MS, 38% for LS, and 54% for MU. Similarly, th e enzyme activity was reduced in macrophages; 35%, 86%, and 73%, for L S, MU, and PU. respectively. In contrast, the fat-rich diets elevated G6PDH activity in the lymphoid organs; by 42% in the spleen due to LS and by 131%, 35%, and 56% in the thymus due to LS, MU, and PU, respect ively. Fat-rich diets decreased the activity of G6PDH in liver. 42%, 6 8%, and 39% for MS, MU, and PU, respectively. Some of the changes in G 6PDH activity induced by the fat-rich diets occur through the mechanis ms of mRNA abundance.