Intracellular pH regulation in epithelial cells.

The regulation of intracellular pH (pHi) in epithelial cells is expected to be extremely important because virtually every biological process is pH sensitive. In addition, changes in pHi may be important in modulating transepithelial solute transport, in modifying biochemical or endocrinological function, and in controlling cell growth and differentiation. Certain epithelial cells are special­ ized for transporting acid/base equivalents through the cell, from one side of the epithelium to the other. In these cells pHi regulation may be intimately in­ terwoven with transepithelial acid/base traffic. This brief review will be con­ fined to ion-transport processes, studied in intact epithelial cells, that affect pHi regulation. Other reviews have considered epithelial acid/base transport studies at the level of whole epithelia (26) or isolated membrane vesicles (5).