The relative mRNA content of ClC‐5, CFTR, megalin, and cubilin, analyzed by semiquantitative real‐time PCR in the renal cortex, was significantly lower in DM rats (0.45 ± 0.06, 0.71 ± 0.05, 0.48 ± 0.14, and 0.49 ± 0.13, n = 7, respectively; P < 0.05) compared with CTRL rats (1.00 ± 0.12, 1.00 ± 0.11, 1.00 ± 0.19, and 1.00 ± 0.07, respectively; n = 4) (Fig. 5A–D). Here, CUBN is linked to diabetes mellitus.