Fig. 6.

8-p-chlorophenylthio-cGMP (8-pCPT-cGMP) inhibits NHE3 activity in Caco-2/bbe cells expressing cGMP-dependent protein kinase (cGK) II. A: NHE3 activity was unchanged in Caco-2/bbe cells infected with control adenovirus [empty vector (EV)] after treatment with 8-pCPT-cGMP (EV+cGMP) compared with untreated cells (EV); n = 4. B: Caco-2/bbe cells showed no detectable levels of endogenously expressed cGK II (not infected) (right lane) and were therefore infected with recombinant adenoviral vector expressing cGK II [cGK II (AV)] (left lane). HIS-cGK II represents purified His₆-tagged cGK II fusion protein as a standard (middle lane). GAPDH was used as a loading control. Results are representative of 3 independent experiments. C: Caco-2/bbe cells expressing cGK II displayed significant inhibition of NHE3 after treatment with 8-pCPT-cGMP (cGMP; 100 μM) compared with untreated control cells (P < 0.05, paired t-tests; n = 4).