Permeability of liver microsomal membranes to glucose.
The permeability of rat liver microsomes to glucose has been studied by using (14)C-labelled D-glucose and a light-scattering technique. 1) The microsomal intravesicular apparent isotope space for D-glucose (1mM; after 5 min incubation at 22 degrees C) was 2.34 microl/mg protein, i.e., approximately 72% of the apparent water space. 2) Efflux of [(14)C]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
P
Istituto di Patologia Generale, University of Siena, Italy.
Fulceri
R
R
Giunti
R
R
Burchell
A
A
Benedetti
A
A
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism / Q000494:pharmacology; D001834:Body Water / Q000378:metabolism; D002250:Carbon Radioisotopes; D003571:Cytochalasin B / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism; D007424:Intracellular Fluid / Q000378:metabolism; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009005:Monosaccharides / Q000378:metabolism; D010419:Pentamidine / Q000494:pharmacology; D010539:Permeability; D011865:Radioisotope Dilution Technique; D051381:Rats; D017207:Rats, Sprague-Dawley; D014316:Tritium; D014638:Vanadates / Q000494:pharmacology
D002250:Carbon Radioisotopes; D007328:Insulin; D009005:Monosaccharides; D014316:Tritium; D003571:Cytochalasin B; D014638:Vanadates; D010419:Pentamidine; D005947:Glucose; D001205:Ascorbic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid