Figure 6.

The PKA inhibitor H89 completely blocked the CM-induced oxalate transport. C2 cells were UT or were treated apically with CM in the culture medium (1:50 dilution × 24 hours), and then ¹⁴C-oxalate uptake was measured as described in the Concise Methods. C2 cells were also treated apically with H89 (20 µM) for 30 minutes followed by the CM (1:50 dilution × 24 hours) with continued presence of H89 (CM+H89), or with H89 (20 µM) alone for 24.5 hours, and then ¹⁴C-oxalate uptake was similarly measured. Values are means±SEM of seven independent experiments each of which was done in triplicate. The CM significantly stimulated ¹⁴C-oxalate uptake, an effect completely blocked by H89 (*P<0.001 for CM compared with UT, CM+H89, and H89, by ANOVA).