LNPEP and Alzheimer disease: Since Ang III and Ang IV have opposite effects (Ang III inhibits GLUT4 and activates IRAP and, vice versa, Ang IV activates GLUT4 and inhibits IRAP), it can be assumed that 27-OHC excess in the brain, as in the case of AD, may reduce brain glucose uptake which has a major impact on brain functioning (Figure 2).