Specific D-glucose transport in sarcolemma vesicles.
The sarcolemmal fraction prepared from rat skeletal muscle consists of osmotically active vesicles that accumulate D-glucose in preference to L-glucose, apparently by facilitated diffusion into intravesicular space. Stereospecific D-glucose uptake by these vesicles is a saturable rpocess, inhibited by phloridzin, by cytochalasin B, and by certain sugars, and enhanced by counterflow. An additional leak pathway permits entry of both D- and L-glucose into the vesicles. Stereospecific D-glucose transport by sarcolemmal vesicles is enhanced to a small extent by insulin, provided the hormone is administered prior to cell disruption. In membranes prepared from insulin-pretreated muscle, Ca2+ produces a small further enhancement. Local anesthetics preferentially inhibit stereospecific D-glucose transport. Apparent uptake of both D- and L-glucose is greater when vesicles are suspended in salt solutions rather than sucrose, an effect attributed to increased functional vesicular volume.
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002474:Cell-Free System; D003571:Cytochalasin B / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009994:Osmolar Concentration; D010695:Phlorhizin / Q000494:pharmacology; D051381:Rats; D012492:Salts / Q000494:pharmacology; D012508:Sarcolemma / Q000378:metabolism*; D013237:Stereoisomerism
D000779:Anesthetics, Local; D007328:Insulin; D012492:Salts; D003571:Cytochalasin B; D003994:Bucladesine; D010695:Phlorhizin; D005947:Glucose; D002118:Calcium