title: Changes in tissue glycogen stores of rats under acute and chronic hypoxia and their relationship to hypoxia tolerance.
abstract: Rats were exposed to simulated altitudes of 3658 m, 4877 m, and 7620 m, for 5 h/d for 30 d at an ambient temperature of 28 degrees C. Blood sugar and tissue glycogen levels were measured--after acute exposure and chronic exposure while either fed ad lib or fasted for 24 h--in liver, kidney, brain, heart, lungs, and skeletal muscles. Glycogen levels were decreased significantly in several tissues under chronic hypoxia in fed animals. In the animals which were fasted 24 h before sacrifice after their 1 month altitude exposure, there was a significant glycogen increase in livers but no change in other tissues. In fasted, acute-exposed animals, glycogen decreased in hearts while in other tissues its levels were unchanged. Hyperglycemia invariably accompanied all conditions of altitude exposures (in fed, fasted, acute, or chronic exposed). Glucose injected i.p. to fed rats as single doses of 20 g/kg body weight 3 h before sacrifice resulted in significantly increased glycogen in all tissues except brain. These glucose injected rats had highly increased resistance to hypoxic stress.
mesh_terms: D000532:Altitude Sickness / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D005215:Fasting; D005947:Glucose / Q000494:pharmacology; D006003:Glycogen / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism; D008297:Male; D051381:Rats; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D008112:Liver Glycogen; D006003:Glycogen; D005947:Glucose