Le Rumeur E, Le Moyec L, de Certaines J D
Laboratoire de Physiologie, Faculté de Médecine, Rennes, France.
Magn Reson Med. 1992 Apr;24(2):335-42. doi: 10.1002/mrm.1910240214.
ATP synthesis from PCr through creatine kinase reaction was measured in vivo in rat leg muscle using 31P NMR magnetization transfer and progressive saturation. Both techniques determined a spin-lattice relaxation time for PCr of 3 s at rest and an identical forward rate constant of 0.22-0.26 s-1. In stimulated muscles, magnetization transfer showed that flux was not changed with a steady-state PCr of 54% of initial level. During stimulation inducing a PCr decrease to 38% of initial value, flux was significantly lowered by 30%. These findings could result from an accumulation of ions and water increases or from compartmentation of ATP and PCr in different pools either in the muscle cell or in the different muscle fibers. In addition, these results could reinforce the hypothesis against a crucial role for creatine kinase shuttle in the ATP supply in skeletal muscle.
利用31P核磁共振磁化转移和渐进饱和技术，在大鼠腿部肌肉中对体内通过肌酸激酶反应由磷酸肌酸（PCr）合成三磷酸腺苷（ATP）的过程进行了测量。两种技术均测定出，静止时PCr的自旋晶格弛豫时间为3秒，正向速率常数相同，为0.22 - 0.26秒-1。在受刺激的肌肉中，磁化转移显示，当稳态PCr为初始水平的54%时，通量没有变化。在刺激过程中，当PCr降至初始值的38%时，通量显著降低了30%。这些发现可能是由于离子积累和水分增加，或者是由于ATP和PCr在肌肉细胞或不同肌纤维的不同池中的分隔所致。此外，这些结果可能会强化反对肌酸激酶穿梭在骨骼肌ATP供应中起关键作用这一假说。
