LOW ANTIOXIDANT ENZYME GENE-EXPRESSION IN PANCREATIC-ISLETS COMPARED WITH VARIOUS OTHER MOUSE-TISSUES

Using a sensitive Northern blot hybridization technique, gene expressi on of superoxide dismutase (SOD), catalase, and glutathione peroxidase was studied in pancreatic islets and for comparison in various other mouse tissues (liver, kidney, brain, lung, skeletal muscle, heart musc le, adrenal gland, and pituitary gland). Gene expression of the antiox idant enzymes was usually in the range of +/-50% of that in the liver. Only in pancreatic islets gene expression was substantially lower. Th e levels of the cytoplasmic Cu/Zn SOD and the mitochondrial Mn SOD gen e expression were in the range of 30-40% of those in the liver. Glutat hione peroxidase gene expression was 15%, and catalase gene expression was not at all detectable in pancreatic islets. These low levels of a ntioxidant enzyme gene expression may provide an explanation for the e xtraordinary sensitivity of pancreatic beta cells towards cytotoxic da mage by diabetogenic compounds and during the development of human and animal diabetes.