Letellier M, Brière N, Plante G E, Petitclerc C
Can J Physiol Pharmacol. 1987 Jun;65(6):1151-6. doi: 10.1139/y87-182.
Several studies have suggested that the brush border membrane alkaline phosphatase is involved in the renal reabsorption of inorganic phosphate along the proximal convoluted tubule. However, other studies on the influence of l(-)bromotetramisole, an inhibitor of alkaline phosphatase, upon phosphate transport into brush border membrane vesicles have failed to show an involvement of alkaline phosphatase. The present experiments were designed to demonstrate that the MDCK (Madin, Darby, canine, kidney) cell line can be used as an alternative model to study phosphate transport, to examine the effect of l(-)bromotetramisole and the role of alkaline phosphatase. MDCK cell monolayers were concomitantly used for alkaline phosphatase activity measurement and phosphate transport analysis. While alkaline phosphatase activity increases by 37-fold from day 2 to day 8 of culture, reaching a plateau at day 10, the sodium-dependent phosphate transport into the cell monolayers decreases by 2-fold during that same period. The phosphate transport was also studied in the presence of l(-)bromotetramisole at pH 8.5. The sodium-dependent phosphate uptake of inorganic phosphate is reduced by 43% in the presence of l(-)bromotetramisole at day 3 of culture but is not reduced in the 7-day-old culture. Our results suggest a participation of alkaline phosphatase upon phosphate transport in MDCK cell monolayers and indicate that this cell line constitutes a good model to study the relationship between alkaline phosphatase and phosphate transport.
多项研究表明，刷状缘膜碱性磷酸酶参与近端曲管中无机磷酸盐的肾脏重吸收。然而，其他关于碱性磷酸酶抑制剂l(-)溴四咪唑对磷酸盐转运至刷状缘膜囊泡影响的研究未能表明碱性磷酸酶的参与。本实验旨在证明MDCK（麦丁-达比犬肾）细胞系可作为研究磷酸盐转运的替代模型，以检验l(-)溴四咪唑的作用及碱性磷酸酶的作用。MDCK细胞单层同时用于碱性磷酸酶活性测定和磷酸盐转运分析。在培养的第2天到第8天，碱性磷酸酶活性增加37倍，在第10天达到平台期，而在此期间，细胞单层中钠依赖性磷酸盐转运减少2倍。在pH 8.5的条件下，还在l(-)溴四咪唑存在的情况下研究了磷酸盐转运。在培养第3天，在l(-)溴四咪唑存在下，无机磷酸盐的钠依赖性磷酸盐摄取减少43%，但在7日龄培养物中未减少。我们的结果表明碱性磷酸酶参与了MDCK细胞单层中的磷酸盐转运，并表明该细胞系是研究碱性磷酸酶与磷酸盐转运之间关系的良好模型。
