An electron microscopic and biochemical study of the effects of glucagon on glycogen autophagy in the liver and heart of newborn rats (Journal article)

Kondomerkos, D. J./ Kalamidas, S. A./ Kotoulas, O. B.


The effects of glucagon on the ultrastructural appearance and acid glucosidase activities in the liver and heart of newborn rats were studied. Liver or heart glycogen-hydrolyzing activity of acid glucosidase increased 3 hours after birth and gradually decreased from 3 to 9 hours. Maltose-hydrolyzing activity of acid glucosidase also rose 3 hours after birth, maintained a plateau between 3 and 6 hours, and fell at 9 hours. The administration of glucagon increased autophagic activity in the hepatocytes at the age of 6 hours. Glycogen inside the autophagic vacuoles was decreased, apparently due to the increased glycogen degradation. Glycogen-hydrolyzing activity was elevated in both the liver and the heart. Maltose-hydrolyzing activity was elevated in the liver, but not in the heart. The results of this study suggest that the glycogen-hydrolyzing and maltose-hydrolyzing activities of acid glucosidase are due to different enzymes. Glucagon's effect on the glycogen-hydrolyzing acid glucosidase activity and autophagosomal morphology is similar in both the liver and the heart.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικής
Keywords: Animals,Animals, Newborn,Autophagy/*drug effects,Glucagon/*pharmacology,Glucosidases/metabolism,Glycogen/*metabolism,Heart/drug effects/physiology,Hepatocytes/drug effects/metabolism/ultrastructure,Liver/drug effects/*metabolism/ultrastructure,Maltose/metabolism,Microscopy, Electron,Myocardium/*metabolism/ultrastructure,Protein Synthesis Inhibitors/*pharmacology,Rats,Time Factors
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/23915
ISSN: 1059-910X
Link: http://www.ncbi.nlm.nih.gov/pubmed/14722905
http://onlinelibrary.wiley.com/store/10.1002/jemt.20000/asset/20000_ftp.pdf?v=1&t=h1ym2otu&s=baa2c067da9c06303add4a48b0b7fd11905f3150
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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