Distinction between chloride-dependent transport systems for taurine and β-alanine in rabbit ileum

L. K. Munck, B. G. Munck

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    Abstrakt

    This study describes the influx of taurine and β-alanine across the brush-border membrane of rabbit distal ileum. The kinetics of J(mc/Tau) [concentration at which half-maximal activation occurs (K( 1/2 )) = 41 μM and J(max) = 24 nmol · cm-2 · h-1] are consistent with the kinetics of taurine uptake by jejunal brush-border vesicles. The taurine carrier differs from the β-alanine carrier by being insensitive to leucine inhibition and by the jejunoileal variation of influx along the small intestine. The K( 1/2 ) for sodium and chloride activation of the β-alanine carrier (48 and 8 mM, respectively) differ markedly from the values reported for the taurine carrier. In addition, taurine is not transported by the β-alanine carrier. Thus the study demonstrates that the taurine and β-alanine carriers are separate entities, and it adds to the imino and the taurine carriers the β- alanine carrier as a third chloride-dependent intestinal transporter of amino acids.

    OriginalsprogEngelsk
    Sider (fra-til)G609-G615
    TidsskriftAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
    Vol/bind262
    Udgave nummer4 25-4
    StatusUdgivet - 1 jan. 1992

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