Certain brain regions contain specialised glucose sensing (GS) neurons that detect falling blood glucose concentrations. Recent studies suggest that there are parallels between these GS neurons and pancreatic β-cells, in that glucokinase, the ATP-sensitive K+ channel and AMPK are all thought to play an integral part (1). AMPK is a serine/threonine kinase composed of α, β and γ subunits, of which there are multiple isoforms (2α, 2β and 3γ-subunits), and has been described as an intracellular “fuel gauge”, activated by either an increase in AMP, or a decrease in the ATP:AMP ratio . Several groups have suggested that AMPK controls GS at the cellular and whole body level (2, 3), yet little is known about the downstream mechanisms of AMPK in these neurons. We have been studying hypothalamic GS using the gonadotropin-releasing hormone (GnRH)-secreting GT1-7 cell line allowing detailed examination of the molecular mechanisms of GS and the role of AMPK. We have assessed GT1-7 cell GS by electrophysiological recording using the perforated patch configuration and gene/protein expression using qRT-PCR and Western blotting, respectively. Kinase activity was measured by radiolabelled activity assay. Furthermore, we have assessed whole body glucose counterregulation in mice using single-catheter hyperinsulinaemic-hypoglycaemic clamp study. To investigate the role of AMPK is GT1-7 cell GS, we generated stable cell lines with knockdown of α2AMPK using lentiviral delivery of short hairpin RNA (shRNA) or a control non-targeting shRNA. Suppression of α2AMPK expression led to decreased AMPK activation during low glucose treatment of infected GT1-7 cells (0.5 mM;n=6). Furthermore, GS, as measured by changes in electrical activity, was significantly blunted and shifted toward a lower glucose concentration, correlating with previous studies of GS neurons in ex vivo slices. We also observed a significant reduction in UCP2 mRNA expression in α2AMPK shRNA-treated cells (n=3), indicating that UCP2 may be involved in GS. To investigate this, we utilised genipin, a pharmacological inhibitor of UCP2 on wildtype GT1-7 cells. Genipin reversed the effects of low glucose on electrical activity (n=5), indicating that UCP2 activity may be required for GS. To determine whether UCP2 activity is required for whole body GS, whole body UCP2 knockout mice underwent hyperinsulinaemic-hypoglycaemic clamp study. UCP2 -/- mice required significantly greater exogenous glucose during the clamp study, indicating a poor response to hypoglycaemia. This was mediated by blunting of the glucagon and adrenaline response to hypoglycaemia (n=8). Together, these data indicate that the AMPK-UCP2 pathway may be important for GS and hypoglycaemia counterregulation in diabetes.