Fig. 4. Effect of dibutyryl cAMP (dbcAMP) or dibutyryl cGMP (dbcGMP) on the expression of Na⁺/K⁺-ATPase, Na⁺/K⁺/2Cl^– cotransporter (NKCC) and Na⁺/H⁺ exchanger-1 (NHE-1) in pavement cells (PVCs) in culture. The cells were exposed to 1–4 mmol l^–1 of the drugs for 24 h. (A) Cell lysates were collected for western blot analysis and (B) the amounts of the respective ion transporter proteins were quantified. Dibutyryl cAMP significantly induced the expression of the three ion transporters. The effect of dbcGMP was negligible. *P<0.05 compared with the control. The results were obtained from more than four independent experiments.