Insulin injected into CNS structures or into the carotid artery: effect on carbohydrate homeostasis of the intact animal.

A synopsis is presented of studies (anatomical, immunohistological, immunochemical, and physiological) that suggested the presence of insulin receptors, native insulin, insulin-responsive cells, and insulin-sensitive glucoregulatory regions (centers) in the CNS. Evidence and consideration at variance with the above were also briefly listed. The controversies related to this new field of investigations are far from settled; they will provide a fertile field for exciting pioneering work for many investigators in the near future.