Apical K+ conductance in maturing rabbit principal cell

The effects of low apical K+ permeability on the low rate of transepithelial K+ secretion were analyzed in perfused cortical collecting ducts (CCDs) isolated from newborn rabbits. Patch-clamp analysis of perfused rabbit CCDs indicated the presence of a maturation-associated increase in the activity of he predominant K+-permeable channel. Furthermore, the increased numbers of conducting apical K+-secretory channels in CCD contributed to the postnatal surge in net K+ secretion.