Nicotinamide adenine dinucleotide phosphate oxidase 4 (NADPH oxidase 4, NOX4) is an important member of the NADPH oxidase family that is primarily responsible for the production of H2O2. The regulation of NOX4 activity is predominantly through protein expression. However, the precise mechanisms by which highly secreting cells maintain NOX4 expression and activity while balancing H2O2 levels within the appropriate physiological range remain unclear.