Co-localization of iNOS and insulin in islets, fenofibrate upregulated iNOS expression in the islet beta cells. Representative confocal microscopy images showed the co-localization of iNOS and insulin in islets. Paraffin-embedded pancreas sections were double immunostained by anti-insulin antibody and TRITC secondary (red) and anti-iNOS antibody and FITC secondary (green). A-C: insulin immunoreactivity; D-F: iNOS immunoreactivity; G-I: co-localization of insulin-iNOS indicated by yellowish fluorescence. Scale bar: 30 μm. Nor, normal rats. Con, water treated obese MSG rats. Fen, fenofibrate treated obese MSG rats.