The effect of anoxic submergence and recovery on circulating levels of catecholamines and corticosterone in the turtle, Chrysemys picta

Abstract

The ability of some freshwater turtles to tolerate prolonged anoxia is well known. The role of hormones in the regulation of the metabolic adjustments that occur during anoxia, however, is unknown. This study examined the changes in plasma glucose, lactate, catecholamine, and corticosterone levels during submergence anoxia and recovery at 22°C in the [ainted turtle, Chrysemys picta. Plasma catecholamine levels increased greatly during anoxia, while corticosterone levels decreased. During recovery from anoxia, plasma catecholamine levels fell rapidly while corticosterone levels increased 10-fold over controls. The results are consistent with a role for the catecholamines and corticosterone in the regulation of glucose metabolism in the turtle during anoxia and recovery, respectively. We hypothesize that the catecholamines function to stimulate hepatic glycogenolysis during anoxia and thereby increase plasma glucose levels. Corticosterone may function in the recovery from anoxia by enhancing the resynthesis of liver glycogen from lactate.