title: Glycogen-containing lysosomes and glycogen loss in the cardiocytes of embryonic and neonatal mice.
abstract: In the mouse embryo the transformation of mesenchymal cells into cardiac myocytes was seen to be indicated by the appearance of glycogen and myosin filaments. In the early force-producing muscle cells, but particularly in the specialized cells destined to become part of the A-V conduction system, the glycogen became abundant. With maturation of the embryo and differentiation of the cardiocytes, the glycogen content decreased in both the force-producing and "conducting" muscle fibers. In late fetal life, and spectacularly after parturition, the loss of glycogen content in the specialized cells was accompanied by the appearance of glycogen-containing lysosomes. Changes in the structure of such lysosomes indicated ongoing dissolution and uncommon use of metabolizable glycogen.
mesh_terms: D000818:Animals; D001283:Atrioventricular Node / Q000166:cytology; D002036:Bundle of His / Q000166:cytology; D002454:Cell Differentiation; D005260:Female; D006003:Glycogen / Q000378:metabolism*; D006346:Heart Septum / Q000166:cytology; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D008854:Microscopy, Electron; D008929:Mitochondria, Heart / Q000378:metabolism; D009200:Myocardial Contraction; D009206:Myocardium / Q000166:cytology*; D011247:Pregnancy
chemical_list: D006003:Glycogen