GCG and Alzheimer disease: Many peptide drugs including copaxone, leuprolide acetate/goserelin (peptide antagonists of GnRH receptor), octreotide (a cyclic octapeptide mimicking natural hormone somatostatin) and glucagon like peptide-1(GLP-1) analog have been evaluated in models of AD substantiating the credibility of peptide drugs for AD [59, 60, 66].