Small-intestinal sulphate absorption is a Na+-dependent process having its highest rate in the ileum; it involves brush-border membrane Na+-sulphate cotransport. Injection of rat ileal mRNA into Xenopus laevis oocytes induced Na+-dependent sulphate uptake in a dose-dependent manner, with no apparent effect on Na+-independent sulphate uptake. For mRNA-induced transport, the apparent Km value for sulphate interaction was 0.6±0.2 mM and that for sodium interaction was 25±2 mM (Hill coefficient: 2.3±0.3). mRNA-induced transport, was inhibited by thiosulphate, but not by phosphate or 4,4,′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS). Using a rat renal Na+-sulphate cotransporter cDNA as a probe [NaSi-1; Markovich et al. (1993) Proc Natl Acad Sci USA 90:8073-8077], the highest hybridization signals (2.3 kb and 2.9 kb) were obtained in size fractions showing the highest expression of Na+-dependent sulphate transport in oocytes. Hybrid depletion experiments using antisense oligonucleotides (from the NaSi-1 cDNA sequence), provided further evidence that rat small-intestinal (ileal) Na+-sulphate cotransport is closely related to rat proximal-tubular brushborder membrane Na+-sulphate cotransport.

Expression of rat ileal Na+-sulphate cotransport in Xenopus laevis oocytes: functional characterization / C. Perego, D. Markovich, F. Norbis, T. Verri, V. Sorribas, H. Murer. - In: PFLÜGERS ARCHIV. - ISSN 0031-6768. - 427:3-4(1994), pp. 252-256. [10.1007/BF00374531]

Expression of rat ileal Na+-sulphate cotransport in Xenopus laevis oocytes: functional characterization

Perego C.;
1994

Abstract

Small-intestinal sulphate absorption is a Na+-dependent process having its highest rate in the ileum; it involves brush-border membrane Na+-sulphate cotransport. Injection of rat ileal mRNA into Xenopus laevis oocytes induced Na+-dependent sulphate uptake in a dose-dependent manner, with no apparent effect on Na+-independent sulphate uptake. For mRNA-induced transport, the apparent Km value for sulphate interaction was 0.6±0.2 mM and that for sodium interaction was 25±2 mM (Hill coefficient: 2.3±0.3). mRNA-induced transport, was inhibited by thiosulphate, but not by phosphate or 4,4,′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS). Using a rat renal Na+-sulphate cotransporter cDNA as a probe [NaSi-1; Markovich et al. (1993) Proc Natl Acad Sci USA 90:8073-8077], the highest hybridization signals (2.3 kb and 2.9 kb) were obtained in size fractions showing the highest expression of Na+-dependent sulphate transport in oocytes. Hybrid depletion experiments using antisense oligonucleotides (from the NaSi-1 cDNA sequence), provided further evidence that rat small-intestinal (ileal) Na+-sulphate cotransport is closely related to rat proximal-tubular brushborder membrane Na+-sulphate cotransport.
NA+-sulfate contransport; rat ileum; xenopus laevis oocytes; expression
Settore BIO/09 - Fisiologia
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/802285
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