High baseline ROMK activity in the mouse late distal convoluted and early connecting tubule probably contributes to aldosterone-independent K+ secretion

Abstract

ROMK-mediated renal K+ secretion is essential for maintaining K+ balance and requires a lumen negative transepithelial potential critically dependent on activity of the ENaC. Using microdissected distal mouse tubules, we demonstrated that baseline apical ROMK activity is high in the DCT2/CNT. Aldosterone-independent baseline ENaC activity is also high in the DCT2/CNT and downregulated by a low-K+ diet, which highlights the important role of the DCT2/CNT in regulating K+ secretion in an aldosterone-independent manner.