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RESEARCH ARTICLE
Contents Vol 17(6)

Inositol transport in mouse embryonic stem cells

B. D. Higgins A and M. T. Kane A B
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- Author Affiliations

A Department of Physiology, National University of Ireland, Galway, University Road, Galway, Ireland.

B Corresponding author. Email: michael.kane@nuigalway.ie

Reproduction, Fertility and Development 17(6) 633-639 https://doi.org/10.1071/RD05021
Submitted: 23 February 2005  Accepted: 5 June 2005   Published: 29 July 2005

Abstract

The uptake of myo-inositol by mouse embryonic stem (ES) cells was measured using [2-3H]myo-inositol. Uptake of myo-inositol by ES cells occurred in a mainly saturable, sodium-, time- and temperature-dependent manner, which was inhibited by glucose, phloridzin and ouabain. Self inhibition by inositol was much greater than inhibition by glucose indicating that transport was not occurring via a sodium-dependent glucose transporter. Uptake rate was much greater than efflux rate indicating a mainly unidirectional transport mechanism. Estimated kinetics parameters for sodium-dependent inositol uptake were a Km of 65.1 ± 11.8 μ mol L−1 and a Vmax of 5.0 ± 0.59 pmol μ g protein−1 h−1. Inositol uptake was also sensitive to osmolality; uptake increased in response to incubation in hypertonic medium indicating a possible role for inositol as an osmolyte in ES cells. These characteristics indicate that myo-inositol transport in mouse ES cells occurs by a sodium-dependent myo-inositol transporter protein.


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