Mitochondrial creatine kinase functional development in post-natal rat skeletal muscle. A combined polarographic/31P NMR study.
Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeletal muscle was assessed both by polarographic measurements of creatine-induced respiration and 31P NMR spectroscopy measurements of phosphocreatine (PCr) synthesis. Creatine-induced respiration was observed in very young rats and increased by 50% to 35 days of age. PCr synthesis was present in 7 day old animals and increased by 300% reaching levels measured in 35 day and adult muscle. Unlike reports showing Mi-CK enzymatic activities but no mitochondrial function in several situations, a concomitant progression of enzymatic activity and mitochondrial function was evidenced during the developmental stages of skeletal muscle Mi-CK in altricious animals. These results correlated with the progressive pattern of muscle differentiation during development of motricity in such animals. The observation that Mi-CK is functional in skeletal muscle mitochondria very early after birth, strongly favors the notion that adaptations in skeletal muscle of Mi-CK knock-out mice occur early.
Kernec
F
F
Laboratoire de RMN en Biologie et Médecine (LRMBM), Faculté de Médecine, Rennes, France.
Nadal
L
L
Rocher
C
C
Mateo
P
P
de Certaines
J
J
Le Rumeur
E
E
D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism*; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D008931:Mitochondria, Muscle / Q000201:enzymology*; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000254:growth & development; D010759:Phosphorus Isotopes; D011048:Polarography; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar
D010759:Phosphorus Isotopes; D003402:Creatine Kinase