Transcellular Cl ⁻ reabsorption in the CD. Type A ICs secrete H⁺ while type B ICs secrete HCO₃⁻. Transport is powered by H⁺-ATPase on the apical and basolateral sides of the cell, respectively. When both are active, the net result is the reabsorption of Cl⁻ through apical pendrin and basolateral Cl⁻ channels. Transepithelial Na⁺ reabsorption by the principal cells (PC) can be balanced either by K⁺ secretion of Cl⁻ reabsorption.