Autocrine C-peptide protects INS1 β cells against palmitic acid-induced oxidative stress in peroxisomes by inducing catalase.

Aims: C-peptide, produced by pancreatic β cells and co-secreted in the bloodstream with insulin, has antioxidant properties in glucose- and hydrogen peroxide (HO)-exposed INS1 β cells. Palmitic acid, the most physiologically abundant long-chain free fatty acid in humans, is metabolized in peroxisomes of β cells accumulating HO that can lead to oxidative stress. Here, we tested the hypothesis that C-peptide protects β cells from palmitic acid-induced stress by lowering peroxisomal HO.