CFTR and diabetes mellitus: The protein content (fold related to control) of ClC‐5, CFTR, TNR‐CFTR and cubilin analyzed by western blotting in the renal cortex was significantly lower in DM rats (0.52 ± 0.10, 0.57 ± 0.06, 0.70 ± 0.03, and 0.86 ± 0.06, respectively; n = 6, P < 0.05) compared with CTRL rats (1.00 ± 0.10, 1.00 ± 0.08, 1.00 ± 0.10, and 1.00 ± 0.01, respectively; n = 6) (Fig. 4A, B, C, and E, respectively).