A RE-ASSESSMENT OF THE REGULATION OF ADIPOSITY AND APPETITE BY THE BRAIN INSULIN SYSTEM. COMMENTARIES

We have provided strong support for the hypothesis that the pancreatic hormone, insulin, provides a signal to the brain indicating the level of adiposity. Because insulin is found in the cerebrospinal fluid (CSF) in direct proportion to plasma levels, and because changes of plasma insulin result in subsequent changes of CSF insulin, we previously hypothesized that the blood-borne insulin signal enters the central nervous system by initially entering the CSF and then diffuses into the brfain. Such a route explained the time lag for influences of insulin upon food intake and body weight.