INS and Alzheimer disease: The increase in brain glucose uptake exerted by lipoic acid feeding poses the question as to whether or not the cyclic disulfide might stimulate insulin signaling: lipoic acid was able to substantially stimulate insulin signaling in the old 3xTg-AD mice, i.e., increase of pIRS-Tyr608/pIRS-S307, pAkt-Ser307, and pGSK3β-Ser9 (Figure 10; components D–F).