cAMP accumulation was compared in HK-2, i2, i25, i14, and i16. Innate cAMP accumulation was similar in all cell lines (Vehicle (VEH)-treated cells). The D1-like receptor agonist fenoldopam (FEN, 1 µmol/L, 30 min) stimulated cAMP accumulation in the coupled cell lines i14 and i16 (*P<0.001 vs others, N=6/group) but not in the uncoupled HK-2, i2, or i25 cells. The D1-like receptor antagonist LE300 (10 µmol/L) had no effect alone, but reversed the FEN stimulation observed in i14 and i16.