GHRL and Parkinson disease: Indeed, accumulating evidence has demonstrated the neuroprotective effects of ghrelin in multiple rodent models of PD, including MPTP-induced PD mice,560,566–568 6-OHDA-induced PD rats,569,570 and A53T α-synuclein transgenic mice.571 These beneficial effects are attributed to its ability to promote autophagy, enhance mitochondrial biogenesis and bioenergetics, mitigate neuroinflammation, and inhibit apoptosis.560,566–569