INSR and Insulin resistance: Indeed, in brain explants, BPA induced an increase in insulin levels in both hippocampus and prefrontal cortex, but decreased insulin receptor expression, insulin receptor substrate 1 (IRS1), AKT, GSK3β, and extracellular signal-regulated kinases (ERK) phosphorylation, implicated in the glucose transport and consequently in the development of brain insulin resistance [72].