title: Muscle fiber contractile type influences the regulation of mitochondrial function.
abstract: Mitochondrial respiratory rates and regulation by phosphate acceptors were studied on permeabilized fiber bundles differing in their myosin heavy chain profiles. The acceptor control ratio, an indicator of oxidation to phosphorylation coupling, and mitochondrial K(m) for ADP were the highest in type I, intermediate in mixed IIa/IIx and the lowest in IIx and predominantly IIb fiber bundles. A functional coupling between mitochondrial creatine kinase and oxidative phosphorylation occurred in type I and IIa/IIx fiber bundles, exclusively. Our study suggests that mitochondrial functioning in fast IIa fibers is closer to that of the slow/I than fast IIx or IIb fibers.
authors.affiliation: INRA, Unité Mixte de Recherche Systèmes d'Elevage et Nutrition Animale et Humaine, Domaine de la Prise, Saint-Gilles, France.
authors.forename: Naig
authors.initials: N
authors.lastname: Gueguen
authors.forename: Louis
authors.initials: L
authors.lastname: Lefaucheur
authors.forename: Martine
authors.initials: M
authors.lastname: Fillaut
authors.forename: Patrick
authors.initials: P
authors.lastname: Herpin
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D019069:Cell Respiration / Q000502:physiology*; D003401:Creatine / Q000494:pharmacology; D003402:Creatine Kinase / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000378:metabolism*; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology* / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology* / Q000378:metabolism*; D011817:Rabbits
chemical_list: D000244:Adenosine Diphosphate; D003402:Creatine Kinase; D003401:Creatine