Glucose transport by uterine plasma membranes.
Uterine plasma membrane preparations were obtained by centrifugation on discontinuous sucrose gradients. The specific activity of the plasma membrane marker 5'-nucleotidase was increased 10-fold while the specific activity of glucose-6-phosphatase was increased 3-fold. Electron microscopy showed mainly closed vesicles having diameters mainly in the range of 0.1 to 0.4 micron and an absence of other recognizable organelles such as mitochondria. D-Glucose transport was inhibited by sulfhydryl reagents, phloretin, and cytochalasin B. Uptake was prevented at high osmotic pressures. The Km of glucose transport was 12.2 +/- 1.1 mM. Studies of the inhibition of [3H]cytochalasin B binding by D-glucose indicated that the value of the Kd of the cytochalasin B-transporter complex was larger than 1 microM. These data demonstrate the potential usefulness of these preparations in the study of glucose transport in rat uterus and its control by steroid hormones.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003571:Cytochalasin B / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D008854:Microscopy, Electron; D009004:Monosaccharide Transport Proteins; D010693:Phloretin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014599:Uterus / Q000166:cytology*
D002352:Carrier Proteins; D009004:Monosaccharide Transport Proteins; D003571:Cytochalasin B; D010693:Phloretin