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Absence of relationship between the postnatal development of ileal active taurocholate transport and microvillus

J E Heubi1, J L Fellows

  • 1Department of Pediatrics, University of Cincinnati College of Medicine, Ohio.

Journal of Developmental Physiology
|March 1, 1990
PubMed

Insights

Changes in rat ileal bile salt transport during development are not due to alterations in microvillus membrane fluidity. This study investigated bile salt uptake and membrane fluidity in young rats, finding no correlation.

Area of Science:

  • Physiology
  • Biochemistry
  • Developmental Biology

Background:

  • Active bile salt transport in the ileum is crucial for nutrient absorption and enterohepatic circulation.
  • The development of this transport system is complex and may involve changes in membrane properties.
  • Microvillus membrane fluidity is a key factor influencing membrane protein function.

Purpose of the Study:

  • To investigate the relationship between microvillus membrane fluidity and the development of active bile salt transport in the rat ileum.
  • To determine if changes in membrane fluidity correlate with observed changes in taurocholate uptake during postnatal development.

Main Methods:

  • Concurrent measurements of ileal microvillus membrane vesicle transport and fluorescence anisotropy were performed.
  • Vesicles were isolated from rats of various ages during the third postnatal week.
  • Taurocholate uptake was measured under different ionic gradients (NaCl and KCl).

Main Results:

  • Taurocholate uptake showed comparable results with NaCl and KCl gradients at 14 and 18 postnatal days.
  • A 'sodium effect' was observed at 20 days and an 'overshoot' at 21 days with NaCl gradients.
  • No significant changes in fluorescence anisotropy (membrane fluidity) were detected between postnatal days 14 and 21.

Conclusions:

  • The observed developmental changes in ileal active bile salt transport are unlikely to be modulated by alterations in microvillus membrane fluidity.
  • Postnatal development of bile salt transport involves mechanisms independent of changes in membrane fluidity.

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