I read this today: http://medicalxpress.com/news/2013-01-onset-alzheimer-memory-loss.html
It's about Alzheimer disease and how exercise slows (and prevents) Alzheimer's disease. Apparently they discovered that during exercise CRF is released and this slows down progression.
So I went to search whether they did some experiments with CRF in Parkinson's disease. I found following article from 2007: http://www.ncbi.nlm.nih.gov/pubmed/17650114
So yes, they did and results were very very good. Usually people treat rodents with some substance and then they poison their brains. However, in this research they gave CRF 7 days after poisoning and still it was shown to reverse lesions. So very promising, but I don't know whether there are clinical research done with this or whether there are meds based on this. I will try to find out and post here if I manage to find.