Cellular influx of sulfobromophthalein by the biliary epithelium carcinoma cell line Sk-Cha-1 reveals kinetic criteria of a carrier-mediated uptake mechanism |
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| Authors: | W Stremmel J Falbrede H E Diede C Elsing |
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| Affiliation: | Department of Internal Medicine, Heinrich Heine University, Düsseldorf, F.R.G. |
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| Abstract: | Cellular uptake of the cholephilic organic anion sulphobromophthalein (BSP) by the human biliary epithelium carcinoma cell line Sk-Cha-1 was examined at 37 degrees C. In confluent monolayer cultures the cellular influx rate of increasing concentrations of [35S]BSP followed saturation kinetics with a Km value of 18 microM and a Vmax value of 243 pmol.min-1.mg protein-1. Uptake of [35S]BSP was competitively inhibited by the presence of bilirubin diglucuronide, but not by taurocholate or cholate. Furthermore, uptake was temperature dependent with maximal cellular influx rates at 37 degrees C. |
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