Meeting Abstract
P2.105 Wednesday, Jan. 5 AMP-activated protein kinase: State-dependent changes in expression in the golden-mantled ground squirrel, C. lateralis BATEMAN, J.L.*; HEALY, J.E.; FLORANT, G.L.; HANDA, R.J.; Colorado State Univ., Ft. Collins; Colorado State Univ., Ft. Collins; Colorado State Univ., Ft. Collins; Univ. of Arizona Coll. of Med., Phoenix jlbatema@rams.colostate.edu
AMP-activated protein kinase (AMPK) serves as a metabolic energy sensor which stimulates catabolic pathways while inhibiting anabolic pathways in order to maintain energetic equilibrium. AMPK is a key component of the food intake pathway; phosphorylated AMPK acts on orexigenic and anorexigenic neurons in the hypothalamic arcuate nucleus (ARC), leading to positive energy balance. The golden-mantled ground squirrel is a mammalian hibernator which ceases food intake and undergoes torpor during winter months. Since AMPK helps to regulate food intake in hibernators in the summer, it may act to suppress food intake during hibernation. We examined ARC AMPK expression in summer 3-day fasted and summer fed squirrels using immunohistochemistry (IHC). We hypothesized that neurons of fasted animals would express more AMPK than summer fed animals. Our preliminary IHC results show a trend towards higher active AMPK levels in fasted animals, but this was not significant. IHC was also performed on brain slices from torpid and euthermic winter ground squirrels. We hypothesized that torpid squirrels would express AMPK at lower levels compared to winter euthermic animals, since enzyme activity is suppressed at low body temperature. Our results show no significant differences between these two groups. Finally, summer AMPK expression was compared to AMPK expression in winter. We found higher expression of AMPK in summer animals than winter animals. We conclude that AMPK expression differs between summer and winter states, but it is not altered by torpor state in winter animals. This work was supported by NIH NS039951 grant to RJH and NIH R25DK067017 to GLF.
