Carbohydrate Metabolism in Fed and Fasted Rats Exposed to an Altitude of 12,470 Feet

Abstract

Blood sugar levels and the glycogen content of liver, heart, skeletal muscle, diaphragm and kidney of both fed and fasted sea level control rats were compared with those of fed and fasted rats (P) born at sea level and then exposed to an altitude of 12,470 feet for various periods of time, and with those of fed rats (F₂) of the second filial generation born and maintained at altitude. In the P animals after short-term (24 and 72 hr.) exposure, liver, heart, muscle and diaphragm glycogen was markedly decreased in the fed animals as compared with the fed sea level controls, and markedly increased in the fasted hypoxic animals as compared with the fasted sea level controls. In fed P animals after long-term exposure, liver, heart, muscle and diaphragm glycogen was the same as in fed controls after 2 and 6 months at altitude, and became markedly lower than in the controls after 10 months. In the F₂ rats, liver and muscle glycogen was markedly decreased when compared with the controls; in contrast, cardiac glycogen content was significantly higher in these F₂ rats than in the controls. Changes were not observed in kidney glycogen. Hyperglycemia was observed in all P rats after 24 hours, and hypoglycemia after 72 hours at altitude. In the long-term experiments glycemia was the same in experimental (P and F₂) and control rats.