Regulation of Na+/H+ Exchange Activity by Adaptive Mechanisms
The plasma membrane Na+/H+ exchanger is found in virtually every type of cell. In epithelia, the antiporter has been reported in the renal tubule, intestine, urinary bladder, gall bladder, colon, and in various cultured kidney cells. 1 The transport system plays a crucial role in vital cell functions such as ionic balance, volume regulation, growth, differentiation, and metabolism and, thus, impacts directly on cellular homeostasis and the well-being of the whole organism. It is not surprising, therefore, that the state of Na+/H+ exchange activity is important in a wide variety of pathophysiological conditions and that its activity is subject to tight control.