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Using Caco-2 Cells to Study Lipid Transport by the Intestine
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Using Caco-2 Cells to Study Lipid Transport by the Intestine

Published on: August 20, 2015

Ontogenesis of taurocholate transport by rat ileal brush border membrane vesicles

J A Barnard, F K Ghishan, F A Wilson

    The Journal of Clinical Investigation
    |March 1, 1985
    PubMed

    Insights

    The transport of taurocholate in rat ileal brush border membrane vesicles is not fully developed in suckling rats but matures by weaning. This process involves a sodium-coupled cotransport system that is fully functional by 3 weeks of age.

    Area of Science:

    • Gastroenterology
    • Developmental Biology
    • Membrane Transport Physiology

    Background:

    • Bile acid absorption is crucial for nutrient digestion and enterohepatic circulation.
    • Understanding the developmental timeline of nutrient transporters is essential for pediatric health.
    • Ileal brush border membrane vesicles are a key model for studying nutrient absorption.

    Purpose of the Study:

    • To investigate the developmental changes in taurocholate transport across the rat ileal brush border membrane.
    • To characterize the transport mechanism and its developmental regulation.
    • To determine the age at which taurocholate transport becomes fully functional.

    Main Methods:

    • Preparation of ileal brush border membrane vesicles from rats of different ages (2, 3, and 6 weeks).
    • Measurement of taurocholate uptake under various ionic gradient conditions (Na+, K+).
    • Kinetic analysis of taurocholate transport using isotope exchange and Woolf-Augustinsson-Hofstee plots.

    Main Results:

    • Taurocholate uptake was similar under Na+ and K+ gradients in 2-week-old rats, indicating immature transport.
    • Significant enhancement of taurocholate uptake with a Na+ gradient was observed in 3- and 6-week-old rats.
    • Kinetic analysis revealed a Na+-dependent, saturable cotransport system in older rats, absent in younger ones.
    • Vmax and Km values indicated a fully developed transport system by 3 weeks of age.

    Conclusions:

    • Taurocholate transport in rat ileal brush border membrane vesicles is mediated by an electroneutral, sodium-coupled cotransport system.
    • This transport system is incompletely developed in suckling (2-week-old) rats.
    • The taurocholate transport system is fully developed by weaning (3 weeks of age).

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