Meeting Abstract
P2.93 Tuesday, Jan. 5 Investigation of seasonal AMP-activated protein kinase expression in golden-mantled ground squirrels (Spermophilus lateralis) BATEMAN, J. L.**; HEALY, J. E.; FLORANT, G. L.; HANDA, R. J.; Colorado State University; University of Arizona College of Medicine, Phoenix jlbatema@rams.colostate.edu
AMP-activated protein kinase (AMPK) is activated in response to high levels of AMP in a cell. Consequently, AMPK initiates catabolic and inhibits anabolic pathways. It is also implicated in the food intake pathway since increased AMPK activity leads to changes in hypothalamic arcuate (ARC) neuron activity. The golden-mantled ground squirrel is a mammalian hibernator which goes into torpor throughout the winter months. During this time, food intake is suppressed. Since AMPK plays a strong role in food intake regulation, it may also be important in food intake suppression during hibernation. We investigated whether AMPK expression in the ARC differs between the summer 3-day fasted and summer fed states using immunohistochemistry (IHC). We hypothesized that neurons of summer 3-day fasted animals would express more AMPK than neurons of summer fed animals. Our preliminary IHC results show a trend towards higher active AMPK levels in fasted animals, but significance was not reached. IHC has also been performed on brain slices from winter-state ground squirrels, including both torpid and euthermic animals. We hypothesized that torpid squirrels would show lower AMPK expression than winter euthermic animals due to suppressed enzyme activity during torpor. Our results show that the two groups were not significantly different. Finally, AMPK expression in summer state animals was compared to AMPK expression in winter. We found that there is more AMPK expression in summer compared to the winter state. We conclude that there are changes in AMPK expression between summer and winter, but once animals enter the winter state, AMPK expression is not altered by torpor. This work was supported by NIH NS039951 grant to RJH and NIH R25DK067017 to GLF.
