FIGURE 3.

Starvation induced changes in claudins. A, Caco-2 cells were incubated in starvation medium for the indicated time and analyzed by Western blotting for claudins. β-actin is shown as a loading control. The protein levels of claudin-2, but not claudin-1, 3, 8, and 13, were reduced during starvation. B, the densitometry analysis was performed using ImageJ software to indicate the relative levels of claudin-2 after starvation. The band density in the control group was set to 1. The graph is representative of more than three independent experiments (*, p < 0.01 versus control). The starvation-induced reduction in claudin-2 protein expression correlated linearly with the increase in Caco-2 TER (C) and the reduction in paracellular flux of urea (D) (p < 0.001).