Neuropeptide Y lowers blood glucose in anaesthetized rats via a Y5 receptor subtype

We have investigated the receptor subtype mediating effects of neuropeptide Y (NPY) on blood glucose concentrations. In anaesthetized rats a 120 min i.v. infusion of 2 microg/kg/min NPY lowered blood glucose by 26 mg/dl. This was mimicked by the same dose of peptide YY (PYY), NPY2-36, PYY3-36 and [Leu31,Pro34]NPY but not by NPY13-36, PYY13-36 or rat or human pancreatic polypeptide. The effects of NPY and [Leu31,Pro34]NPY were not inhibited by 10 microg/kg/min BIBP 3226. Neither treatment significantly altered plasma insulin concentrations. We conclude that NPY lowers blood glucose concentrations via a Y5 receptor subtype, i.e. a subtype which has also been implicated in stimulation of food intake.