title: Non-invasive assessment of oxidative capacity in young Indian men and women: a 31P magnetic resonance spectroscopy study.
abstract: It is generally assumed that men display greater strength and muscle capacity than women. However, previous biochemical and histological studies have shown that men have greater capacity for anaerobic metabolism and women have higher or similar oxidative metabolism. Therefore, in the present study, we estimated oxidative capacity of gastrocnemius muscle and compared in Indian men and women using non-invasive in vivo 31P magnetic resonance spectroscopy (MRS). Healthy subjects (8 young males and 9 females, age-matched) performed plantar flexion exercise within a magnet and MRS measurements of inorganic phosphate (Pi), phosphocreatine (PCr), ADP, and pH of the calf muscles were carried out using a 1.5 T whole-body MRI system. PCr values during recovery were fitted to an exponential curve, and oxidative capacity was calculated using rate constant (k(PCr)), as an index of oxidative phosphorylation. When men and women were compared for different metabolic ratios, ADP, pH, k(PCr) and oxidative capacity, all parameters turned out to be statistically insignificant. The results showed no gender effect on skeletal muscle oxidative metabolism. The study demonstrated the usefulness of such non-invasive method to indirectly measure the oxidative capacity of the muscle based on PCr recovery.
authors.affiliation: NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (INMAS), Defence R & D Organisation, Brig. S. K. Mazumdar Marg, Timarpur, Delhi 110054, India.
authors.forename: Poonam
authors.initials: P
authors.lastname: Rana
authors.forename: Aruna
authors.initials: A
authors.lastname: Varshney
authors.forename: M Memita
authors.initials: MM
authors.lastname: Devi
authors.forename: Pawan
authors.initials: P
authors.lastname: Kumar
authors.forename: Subash
authors.initials: S
authors.lastname: Khushu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007194:India; D007866:Leg / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology*; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes; D010766:Phosphorylation; D010809:Physical Fitness / Q000502:physiology*; D013997:Time Factors
chemical_list: D010710:Phosphates; D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate