We demonstrate that, under different experimental conditions, the presence of PD-linked mutant LRRK2 determines an increase in DA extracellular level in short-time dynamic experiments in PC12 cells, an increase in GH release in SH-SY5Y cells and an increase of DRD1 on cell membrane of both SH-SY5Y cells and striatum of LRRK2G2019S transgenic mice. This evidence concerns the gene LRRK2 and Parkinson disease.