CAT and neuroblastoma: It was shown that treatment of 3T3-1L preadipocytes with melatonin (1 mM) increased activity of catalase and MnSOD [34]; however, Mayo et al. found no change in mRNA levels for antioxidant enzymes, Cu/Zn-SOD, MnSOD, and glutathione peroxidase in nondifferentiated PC12 cells and the human neuroblastoma cells after treatment with 0.1 mM melatonin [35].