[The study of bioenergetics of mouse pregnant uterine muscle by magnetic resonance spectroscopy (MRS)].
To investigate the bioenergetics of uterine muscles in vivo, we examined the energy state of mouse preterm uterus by means of magnetic resonance spectroscopy. Full-term mouse uterus contained ATP, PCr, phospho-di and mono ester (PDE and PME) and inorganic phosphate (Pi). The oxytocin-induced uterine muscle contraction peaks level and positions changed. Multiple peak analysis indicated a muscle contraction induced increase in the Pi concentration and decrease in the PCr concentration. The peak position of Pi was shifted in the contractive state also, indicating that the intracellular pH was lower than in the non-contractive state and this low pH level was recovered within several minutes. There was no change in the AMP peak height in the contractive and non-contractive states. These data indicated that the energetics of mouse uterine muscle was maintained by the ATP-PCr system and acidosis of muscle was recovered within several minutes at rest. The constant AMP peak levels may indicate that phosphorylase is not regulated by AMP, but the phosphorylated phosphorylase kinase and pH levels in the contractive and non-contractive states also may indicate that phosphorylase kinase is not regulated by proteolysis or by the intracellular pH level but by the elevated intracellular calcium ion and calmodulin system.
Department of Obstetrics and Gynecology, Fukui Medical School.
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Negami
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Tominaga
D000818:Animals; D004734:Energy Metabolism; D005260:Female; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008813:Mice, Inbred ICR; D009130:Muscle, Smooth / Q000378:metabolism; D009215:Myometrium / Q000378:metabolism* / Q000502:physiology; D010121:Oxytocin; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism* / Q000502:physiology; D014590:Uterine Contraction / Q000187:drug effects
D010725:Phosphocreatine; D010758:Phosphorus; D010121:Oxytocin