Ozdemir Mahir S, Reyngoudt Harmen, De Deene Yves, Sazak Hakan S, Fieremans Els, Delputte Steven, D'Asseler Yves, Derave Wim, Lemahieu Ignace, Achten Eric
Department of Electronics and Information Systems, MEDISIP, Ghent University-IBBT-IBiTech, De Pintelaan 185 block B, B-9000 Ghent, Belgium.
Phys Med Biol. 2007 Dec 7;52(23):6781-94. doi: 10.1088/0031-9155/52/23/001. Epub 2007 Nov 6.
Carnosine has been shown to be present in the skeletal muscle and in the brain of a variety of animals and humans. Despite the various physiological functions assigned to this metabolite, its exact role remains unclear. It has been suggested that carnosine plays a role in buffering in the intracellular physiological pHi range in skeletal muscle as a result of accepting hydrogen ions released in the development of fatigue during intensive exercise. It is thus postulated that the concentration of carnosine is an indicator for the extent of the buffering capacity. However, the determination of the concentration of this metabolite has only been performed by means of muscle biopsy, which is an invasive procedure. In this paper, we utilized proton magnetic resonance spectroscopy (1H MRS) in order to perform absolute quantification of carnosine in vivo non-invasively. The method was verified by phantom experiments and in vivo measurements in the calf muscles of athletes and untrained volunteers. The measured mean concentrations in the soleus and the gastrocnemius muscles were found to be 2.81 +/- 0.57/4.8 +/- 1.59 mM (mean +/- SD) for athletes and 2.58 +/- 0.65/3.3 +/- 0.32 mM for untrained volunteers, respectively. These values are in agreement with previously reported biopsy-based results. Our results suggest that 1H MRS can provide an alternative method for non-invasively determining carnosine concentration in human calf muscle in vivo.
肌肽已被证明存在于多种动物和人类的骨骼肌和大脑中。尽管赋予了这种代谢物各种生理功能，但其确切作用仍不清楚。有人提出，由于在高强度运动疲劳发展过程中接受释放的氢离子，肌肽在骨骼肌细胞内生理pH值范围内起到缓冲作用。因此推测肌肽浓度是缓冲能力程度的一个指标。然而，这种代谢物浓度的测定仅通过肌肉活检进行，这是一种侵入性操作。在本文中，我们利用质子磁共振波谱（1H MRS）来无创地对体内肌肽进行绝对定量。该方法通过体模实验以及对运动员和未经训练志愿者小腿肌肉的体内测量进行了验证。比目鱼肌和腓肠肌中测得的平均浓度，运动员分别为2.81±0.57/4.8±1.59 mM（平均值±标准差），未经训练的志愿者分别为2.58±0.65/3.3±0.32 mM。这些值与先前报道的基于活检的结果一致。我们的结果表明，1H MRS可以提供一种在体内无创测定人小腿肌肉中肌肽浓度的替代方法。
