Abstract: AIMTo observe the effect of acetazolamide on the water transporting function of Xenopus oocytes expressing aquaporin-1. METHODSFifty nL AQP1 cRNA was injected into Xenopus oocytes, then the cells were transferred to low osmotic solution. The swelling of the cells in response to 1×10^-7～1×10^-5 mol·L^-1 acetazolamide was recorded, and the corresponding osmotic water permeability (Pf) was calculated. RESULTSThe Xenopus oocytes expressing AQP1 protein swelled immediately after transferred to low osmotic solution, with the Pf markedly increased to 1.83×10^-2 cm·s^-1. While the Pf of negative group injected with ddH₂O remained as 0.25×10^-2 cm·s^-1. Aquaporin inhibitor HgCl₂ decreased the Pf of AQP1 to 0.64×10^-2 cm·s^-1; After treated with acetazolamide at the dose of 1×10^-7～1×10^-5 mol·L^-1, the Pf decreased in a concentration-dependent manner. CONCLUSIONAcetazolamide decreased the osmotic water permeability induced by AQP1 and inhibited the water transporting function of AQP1 in a dose dependent manner.