Effect of adrenaline on glucose transport in red cells of Rana balcanica.
The characteristics of 3-O-methyl-D-glucose (3-OMG) uptake by frog erythrocytes were studied. 3-OMG transport was increased by adrenaline. Although the transport is inhibited by phloretin, the lack of saturation kinetics suggests that a glucose transporter doesn't exist or that its affinity for glucose is extremely low. Frog Rana balcanica red cells suspended in an isotonic medium containing adrenaline enlarge rapidly to reach a new pH-dependent steady state volume. At pH 8.0, the cells swell less than at pH 7.3. This is explained by a differential pH effect on the two pathways controlling the movement of the cations: as pH becomes more acidic K+ loss decreases. On the contrary as pH becomes more acidic Na+ uptake increases. The increase in glucose transport after osmotic swelling and the inhibition of swelling-induced glucose transport by phloretin suggest that the glucose transport pathway in Rana balcanica erythrocytes may is a volume-activated channel.
Kaloyianni
M
M
Laboratory of Animal Physiology, Zoology Department, School of Biology, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece. kaloyian@bio.auth.gr
Doukakis
I
I
D019325:3-O-Methylglucose / Q000493:pharmacokinetics*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism*; D005947:Glucose / Q000493:pharmacokinetics; D010693:Phloretin / Q000494:pharmacology; D011898:Ranidae / Q000378:metabolism
D019325:3-O-Methylglucose; D005947:Glucose; D010693:Phloretin; D004837:Epinephrine