Figure 1.

Presence of functional sAC in H69 cholangiocytes was demonstrated by bicarbonate‐stimulated cAMP accumulation assay. (A) Confluent H69 cholangiocyte monolayers were incubated in either normal HBSS or chloride‐free HBSS for 30 minutes. The latter reversed the chloride gradient across the plasma membrane and forced AE2 to take up bicarbonate. (B) Total cAMP was measured by an enzyme‐linked immunosorbent assay in the absence or presence of KH7, a specific inhibitor of sAC. Shown here is the average of two quadruplicate experiments. One‐way ANOVA, P = 0.0007. (C) From each independent quadruplicate experiment in (B), sAC‐derived cAMP was calculated (defined as the difference in total cAMP measured in the absence and presence of KH7). Two‐tailed Student t test, P = 0.03. * P < 0.05, **P ≤ 0.01. Abbreviations: AMP, adenosine monophosphate; ATP, adenosine triphosphate; IBMX, 3‐isobutyl‐1‐methylxanthine; PDE, phosphodiesterase.