The permeability of rat liver microsomes to glucose has been studied by using 14C-labelled D-glucose and a light-scattering technique. 1) The microsomal intravesicular apparent isotope space for D-glucose (1 mM; after 5 min incubation at 22°C) was 2.34 μl/mg protein, i.e., approximately 72% of the apparent water space. 2) Efflux of [14C]D-glucose from microsomal vesicles pre-loaded as in 1) and measured by rapid Millipore filtration after dilution (100 fold) in a glucose-free medium revealed that 15 sec after dilution only 15% of intravesicular glucose was still retained by microsomes. 3) Osmotic behaviour of microsomes upon addition of D-glucose measured by a light-scattering technique revealed a glucose influx, saturable at [D-glucose] ≥ 100 mM, and (partially) inhibited by pentamidine and cytochalasin B. Ascorbic acid, L-glucose and other monosaccharides and related compounds also permeated liver microsomes in a fashion similar to D-glucose. These data indicate the existence of a facilitative transport system(s) for glucose in the membrane of liver endoplasmic reticulum vesicles.
Marcolongo, P., Fulceri, R., Giunti, R., Burchell, A., Benedetti, A. (1996). Permeability of liver microsomal membranes to glucose. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 219(3), 916-922 [10.1006/bbrc.1996.0333].
Permeability of liver microsomal membranes to glucose
MARCOLONGO, P.;FULCERI, R.;GIUNTI, R.;BENEDETTI, A.
1996-01-01
Abstract
The permeability of rat liver microsomes to glucose has been studied by using 14C-labelled D-glucose and a light-scattering technique. 1) The microsomal intravesicular apparent isotope space for D-glucose (1 mM; after 5 min incubation at 22°C) was 2.34 μl/mg protein, i.e., approximately 72% of the apparent water space. 2) Efflux of [14C]D-glucose from microsomal vesicles pre-loaded as in 1) and measured by rapid Millipore filtration after dilution (100 fold) in a glucose-free medium revealed that 15 sec after dilution only 15% of intravesicular glucose was still retained by microsomes. 3) Osmotic behaviour of microsomes upon addition of D-glucose measured by a light-scattering technique revealed a glucose influx, saturable at [D-glucose] ≥ 100 mM, and (partially) inhibited by pentamidine and cytochalasin B. Ascorbic acid, L-glucose and other monosaccharides and related compounds also permeated liver microsomes in a fashion similar to D-glucose. These data indicate the existence of a facilitative transport system(s) for glucose in the membrane of liver endoplasmic reticulum vesicles.File | Dimensione | Formato | |
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https://hdl.handle.net/11365/416442