Juel C
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
Physiol Rev. 1997 Apr;77(2):321-58. doi: 10.1152/physrev.1997.77.2.321.
Skeletal muscle and most other tissues possess a membrane transport system mediating a coupled lactate and H+ translocation. Muscle possesses several lactate-proton transporter isoforms of which two have been cloned; however, the main isoform remains to be identified. The isoforms may have different properties and functional roles, but these have not been specifically characterized. The distribution of lactate-proton transport capacity in skeletal muscle is fiber type dependent, with a higher capacity in slow-twitch fibers compared with fast-twitch fibers. During intense muscle activity and in the recovery period, the lactate and H+ effluxes are mainly mediated by the lactate-proton transporter, which reduces the accumulation of lactate in muscle as well as the drop in internal pH suggested to be involved in muscle fatigue. Thus the lactate-proton transporter is of functional importance for pH regulation in association with muscle activity. This carrier is also important for lactate uptake into resting muscle and other tissues; therefore, the carrier distribution is important for the fate of lactate in the body. In addition, the capacity of the lactate-proton transporter can be increased by intense training and is reduced by inactivity; thus the lactate-proton transporter can undergo adaptive changes.
骨骼肌和大多数其他组织拥有一种膜转运系统，该系统介导乳酸和氢离子的偶联转运。肌肉拥有几种乳酸-质子转运体亚型，其中两种已被克隆；然而，主要亚型仍有待确定。这些亚型可能具有不同的特性和功能作用，但尚未进行具体表征。骨骼肌中乳酸-质子转运能力的分布取决于纤维类型，慢肌纤维中的转运能力高于快肌纤维。在剧烈肌肉活动期间和恢复期，乳酸和氢离子外流主要由乳酸-质子转运体介导，这减少了肌肉中乳酸的积累以及内部pH值的下降，而pH值下降被认为与肌肉疲劳有关。因此，乳酸-质子转运体对于与肌肉活动相关的pH调节具有重要的功能意义。这种载体对于乳酸进入静息肌肉和其他组织也很重要；因此，载体分布对于体内乳酸的去向很重要。此外，乳酸-质子转运体的能力可通过高强度训练增加，而因不活动而降低；因此，乳酸-质子转运体可发生适应性变化。
