Hibernation reduces pancreatic amylase levels in ground squirrels

Pancreatic enzyme levels in mammals are influenced by food intake and dietary composition. In this study, we examined the activity and expression of pancreatic amylase in a hibernating mammal, a natural model for long-term fasting. Pancreatic tissues were obtained from summer-active 13-lined ground squirrels and hibernating squirrels that had not eaten for at least 6 weeks. Amylase specific activity was reduced by similar to 50% in the torpid hibernators compared with summer squirrels, and immunoblot analysis revealed that amylase protein expression was reduced by similar to40% in the hibernators. Similar reductions in amylase specific activity were observed in interbout euthermic hibernators. These results support a strong influence of food intake on pancreatic enzyme expression in hibernating mammals. The maintenance of basal levels of this key digestive enzyme at similar to 50% of summer values despite the extended winter fast likely facilitates the rapid resumption of digestive function after terminal arousal in the spring. (C) 2002 Elsevier Science Inc. All rights reserved.