Simulation of transport along the distal nephron. A mathematical model of the rat DCT-CNTe-CNTas was used to calculate expected Na⁺ and K⁺ transport using apical Na⁺ and K⁺ permeabilities measured under control (C), low-K (LK), and high-K (HK) conditions. Panels show transepithelial voltage (V_M), luminal concentrations of Na⁺ (C_M(Na)), and K⁺ (C_M(K)) and flows of volume (F_v), Na⁺ (F_k(Na)), and K⁺ (F_K(K)) along the nephron. The segment labeled as DCT corresponds most closely with DCT1 as defined anatomically.