Vanadate stimulates D-glucose transport into sarcolemmal vesicles from rat skeletal muscles.
Vanadate is known to have various insulin-like actions including activation of D-glucose uptake into the skeletal muscle and adipose tissue. In this study, we examined the effect of orthovanadate on D-glucose uptake into sarcolemmal vesicles prepared from rat hind limb skeletal muscles. In the presence of 10 mM vanadate, the initial rate of D-glucose uptake into sarcolemmal vesicles was enhanced 4-5 times above the basal value. Half-maximal concentration for this effect of vanadate was 3 mM. The D-glucose uptake was also stimulated by metavanadate, but not by selenite, selenate, or molybdate. When vanadate was removed from the vesicles by dilution and centrifugation, D-glucose uptake into the vesicles returned to the basal level, indicating that the effect of vanadate was reversible. Saturation curves showed that the Vmax value for the D-glucose uptake was enhanced more than 4-fold by 10 mM vanadate. Therefore, the activation of D-glucose uptake was due, at least in part, to a large increase in the Vmax value. These results suggest that vanadate increases the intrinsic activity (turnover number) of skeletal muscle glucose transporters in a reversible manner.
Okumura
N
N
Department of Medical Biochemistry, Ehime University School of Medicine.
Shimazu
T
T
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D005260:Female; D005947:Glucose / Q000493:pharmacokinetics; D009004:Monosaccharide Transport Proteins / Q000187:drug effects* / Q000378:metabolism; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000187:drug effects* / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology*
D009004:Monosaccharide Transport Proteins; D014638:Vanadates; D005947:Glucose