To eat or not to eat: AMPK regulation of food intake in marmots [Manger ou ne pas manger : règulation par la protéine kinase activée par la 5' adénosine monophosphate de la prise alimentaire des marmottes].

Résumé

Mammals that hibernate (hibernators) including the yellow-bellied marmot (Marmota flaviventris)stop eating throughout winter after nearly doubling their body mass by autumn. The mechanism that regulates food intake in hibernators is unclear. Recently, amp-activated protein kinase (ampk) has been shown to play a role in the regulation of food intake and peripheral energy utilization in mammals. Activation of hypothalamic ampk causes animals to feed. We hypothesized that ampk activator, 5’-aminoimidazole-4-carboxamide 2 b-d-ribofuranoside (aicar), infused intracerebroventricularly (icv) would cause marmots to feed in the winter, when they usually would not. Icv infusion of aicar into marmots caused significant increase in food intake. Once the infusion finished, animals returned to torpor at 5 c. The control animal (saline infused) did not eat and underwent torpor bouts at a high ambient temperature. Our results suggest that ampk is involved in regulating energy balance and food intake in hibernators and that the neural pathways involved in feeding and eliciting torpor interact in a reciprocal relationship.