Glycogenolysis during anoxia in aged mouse heart.
Myocardial glycogen mobilization in response to anoxia has been studied in open-chested C57Bl/6NCrl male mice 6 and 24 months of age. During the 1st minute without oxygen, old animals utilized glycogen more rapidly than did young animals. However, during the 2nd minute of anoxia, young animals continued to utilize cardiac glycogen, whereas old animals did not. A direct correlation was noted between glycogen utilization and activation of myocardial phosphorylase activity (A+B forms). Moreover total myocardial phosphorylase declined during anoxia in old animals while showing no significant change in their younger counterparts. This age-related defect in glycogen mobilization suggests altered tolerance to anoxia in aged animals. The inability to mobilize myocardial glycogen may stem from the existence of an altered form of phosphorylase or from an altered environment in the aged heart.
D000375:Aging; D000818:Animals; D006003:Glycogen / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D051379:Mice; D009206:Myocardium / Q000378:metabolism*; D006005:Phosphorylases / Q000032:analysis
D006003:Glycogen; D006005:Phosphorylases