One consideration is a pathobiological model described in Alzheimer’s disease (AD) and mild cognitive impairment as “type 3 diabetes” where there is deficient insulin signaling in the brain with downregulation of insulin receptors and insulin-like growth factor 1 (IGF-1), with IGF-1 production in the liver controlled by pulsatile growth hormone release [56]. Here, IGF1 is linked to early-onset autosomal dominant Alzheimer disease.