IRS1 and Alzheimer disease: Although brain insulin signaling is typically reduced in AD, peripheral tissues can show early hyperactivation as a compensatory mechanism under systemic insulin resistance (e.g., glucagon‐like peptide‐1 [GLP‐1]–mediated upregulation of insulin receptor beta, insulin receptor substrate 1, and glucose transporter type 4 in adipose tissue).64, 65, 66