ABSTRACT
<p><b>AIM</b>To study the endogenous mechanism for the inhibition of aquaporin-1 expression in rat renal proximal tubule epithelial cells in response to acetazolamide.</p><p><b>METHODS</b>Primary cultured rat renal proximal tubule epithelia cells were divided into two groups: one was subjected to 1 x 10(-5) mol.L-1 acetazolamide, the other served as normal control. When grown to sub-confluency, the cells were disintegrated to perform isoelectrofocusing electrophoresis in order to find the differential proteins induced by the acetazolamide treatment. The differential proteins were defined by peptide mass fingerprinting technology.</p><p><b>RESULTS</b>Two differential proteins were found in the cell disintegrant. The pI 3.8 protein was reduced after treatment, which showed 21.4% similarity with the brush border membrane myosin from rat brain and testis, and 27% with glycogen phosphorylase; The pI 5.5 protein was increased on the contrary, with 20% similarity to phosphatidylinositol transfer protein alpha isoform.</p><p><b>CONCLUSION</b>Acetazolamide inhibited AQP1 expression probably by affecting the expression of pI 3.8 and pI 5.5 proteins.</p>