Meeting Abstract

50.5  Monday, Jan. 5  Expression and phosphorylation of AMPK and ACC in fed and fasted golden-mantled ground squirrels (GMGS) HEALY, Jessica E*; DIAZ, Yvonne; FLORANT, Gregory L; Colorado State University; New Mexico State University; Colorado State University jehealy@simla.colostate.edu

The golden-mantled ground squirrel (GMGS) is a mammal that hibernates (hibernator) and has a robust annual cycle of mass gain and loss controlled primarily by food intake. There are many pathways, enzymes, and hormones implicated in the control of food intake in hibernators, and the hypothalamic arcuate nucleus is a main control center of feeding. The enzymes adenosine monophosphate-activated protein kinase (AMPK) and acetyl coenzyme-A carboxylase (ACC) have been implicated in control of feeding in hibernators and other mammals. AMPK is a cellular energy sensor which responds to the increased levels of AMP caused by fasting. When AMPK is activated by phosphorylation, it causes a phosphorylation and deactivation of ACC, resulting in an increase in food intake. We hypothesized that GMGS fasted for a short time during the summer would have increased levels of active (pAMPK) and total AMPK, with associated increases in the inactive form of ACC (pACC). Fourteen GMGS were randomly assigned to one of four groups (Control (fed), 1-day fast, 3-day fast, and 5-day fast), and sacrificed after their assigned fasting time. Western blots were used to determine expression of AMPK, pAMPK, ACC, and pACC in muscle, white adipose tissue (WAT), liver, and the arcuate nucleus region of the hypothalamus. We found that pACC and AMPK increased, and ACC decreased as expected, but found no clear trend in pAMPK with fasting. These data indicate fasting changes the expression of AMPK and ACC in several tissues. This change in expression suggests a change in cellular energy level which may activate food intake pathways.