GDNF and Parkinson disease: Other substances that have been tested in in vitro and/or in vivo studies for PD include N-3,4-bis(pivaloyloxy)-dopamine (BPD), glial cell line-derived neurotrophic factor (GDNF), basic fibroblast growth factor (bFGF), coenzyme Q10 (CoQ10), resveratrol, and apomorphine andropirinole [10].