title: [Age differences in the ultrastructure of the myocardium of thyroxine treated rat].
abstract: Ultramicromeasuring studies were made on different sites of thyroxine-induced hypertrophic myocardium of rats of different ages (6 and 26 months of age). In the resting stage, the area ratio of mitochondria to myofibrils was significantly smaller in old rats and also in the apex. In rats receiving thyroxine, the ratio was not increased in the young rats, but was markedly increased in the old, reaching the value in the young rat, suggesting a decrease in the reserve power of the myocardial mitochondria in the old rats.
authors.affiliation: Institute for Medical Science of Aging, Aichi Medical University.
authors.forename: K
authors.initials: K
authors.lastname: Kohtani
mesh_terms: D000367:Age Factors; D000818:Animals; D006321:Heart / Q000187:drug effects*; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000648:ultrastructure*; D009206:Myocardium / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000494:pharmacology*
chemical_list: D013974:Thyroxine