Also, while Exendin-4 normalized the hippocampal expression levels of total GSK-3β in the i.c.v. STZ-injected rat AD/T2DM model (Chen et al., 2012), liraglutide did not reduce the elevated GSK-3β pools in Aβ-based AD animals (McClean and Holscher, 2014a; Qi et al., 2016; Holubova et al., 2019). This evidence concerns the gene GSK3B and type 2 diabetes mellitus.