Effects of acetazolamide and anordiol on osmotic water permeability in AQP1-cRNA injected Xenopus oocytel

AIM: To study the effects of acetazolamide and anordiol on osmotic water permeability in aquaporin I (AQP1)-cRNA injected Xenopus oocyte and their mechanisms. METHODS: AQP1 gene constructed in pBluescript was transcripted into cRNA in vitro and then the cRNA was injected in Xenopus oocytes. The effects of acetazolamide and anordiol on the water transport function of AQP1 were observed by assaying the osmotic swelling of oocytes. In addition, their effects on protein expression of AQP1 were quantitatively investigated by Western blotting method. RESULTS: After incubation for 15 min or 72 h, acetazolamide, a carbonic anhydrase inhibitor, equally reduced the water permeability of AQP1-cRNA injected oocyte in a dose-dependent manner. After incubation for 72 h, anordiol, an antiestrogen with partial estrogenic activity, reduced the osmotic water permeability dose dependently as well; however, no discernable action was observed after incubation with anordiol for 15 min. The Western blotting analysis showed that acetazolamide did not influence the protein expression of AQP1. However, after incubation for 72 h with anordiol (10 mumol/L), the quantity of AQP1 in the oocyte membrane was decreased dramatically (P<0.05). CONCLUSION: Both acetazolamide and anordiol inhibited the osmotic water permeability of AQP1-RNA injected oocyte, but their mechanisms were different. Acetazolamide functionally inhibited the osmotic water permeability of AQP1, whereas anordiol primarily decreased the amount of AQP1 protein in the oocyte membrane.