MAOB and Parkinson disease: Another glitazone, pioglitazone, has been shown to interfere with the activation of MPTP by inhibiting monoamine oxidase B (MAO-B), which converts MPTP to its active metabolite MPP+ (Quinn et al., 2008) suggesting that the glitazones as a drug class may be neuroprotective in the MPTP mouse model by a mechanism that is irrelevant to PD pathogenesis.