The complete mechanism behind this observation is unclear, but leptin infusion directly into the cerebral ventricles, at a dose and route that is believed to act locally in the brain and not outside the CNS, attenuates hyperglycaemia in rats with profound diabetes due to severe insulin deficiency; this effect was independent from leptin's effect on feeding and hepatic insulin sensitivity, but involved reduced HGP and increasing glucose uptake into brain, muscle and brown fat74. The gene discussed is LEP; the disease is diabetes mellitus.