GPER1 and Alzheimer disease: Consistent with the IHC data and the gene expression data shown above, the protein expression levels of StAR, HSD3β2, aromatase, HSD17β1, ERβ, and GPER in both OE and AD groups were all significantly elevated (all P-values ≤ 0.007; Fig. 6A–D, F, and G), especially OE lesions.