The Insulin Receptor in Astrocytes is Involved in the Entrance of Circulating Insulin into the Brain

Circulating insulin enters into the brain through mechanisms that are not yet entirely understood. We now report that mice lacking insulin receptors (IR) in astrocytes show reduced uptake of circulating insulin and blunted brain responses to this circulating hormone, suggesting that astrocytes form part of the cellular pathway in the entrance of circulating insulin into the brain. Since we previously showed that ablation of IR in astrocytes decreases brain glucose uptake, we conclude that astrocytic IRs regulate uptake of circulating glucose and insulin.