Monensin stimulates sugar transport in avian erythrocytes

Biochim Biophys Acta. 1985 Nov 21;821(1):37-44. doi: 10.1016/0005-2736(85)90150-6.


The cell-medium distribution of the nonmetabolized glucose analog, 3-O-methyl-D-glucose was studied in pigeon erythrocytes. The sodium ionophore monensin increased in parallel and in a dose-dependent manner the influx of hexose and of Na+. These effects were independent of external Ca2+ and there was no alteration in 45Ca influx. If, as suggested previously, hexose transport in these cells is modulated by cytoplasmic Ca2+, the stimulatory effect of monensin on hexose transport may be due to increased mitochondrial Ca2+ efflux via Na+-Ca2+ exchange, owing to the elevation of cytoplasmic Na+. Such a mechanism is consistent with the observed failure of monensin to affect 3-O-methyl-D-glucose transport in cells partially depleted of Ca2+. Monensin also depressed cellular ATP levels but the data favour a Ca2+-dependent mechanism of hexose transport regulation rather than a direct effect of metabolic depletion. The inhibitor of specific-mediated hexose transport, cytochalasin B was found to inhibit equally basal and stimulated 3-O-methyl-D-glucose uptake but there was a cytochalasin B-insensitive uptake component in excess of L-glucose uptake. This appears to reflect a greater diffusional permeability of 3-O-methyl-D-glucose than of L-glucose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-O-Methylglucose
  • Animals
  • Biological Transport, Active / drug effects
  • Columbidae
  • Cytochalasin B / pharmacology
  • Erythrocytes / drug effects
  • Erythrocytes / metabolism*
  • Furans / pharmacology*
  • Kinetics
  • Methylglucosides / blood
  • Monensin / pharmacology*
  • Monosaccharide Transport Proteins / blood*
  • Potassium / blood
  • Sodium / blood


  • Furans
  • Methylglucosides
  • Monosaccharide Transport Proteins
  • 3-O-Methylglucose
  • Cytochalasin B
  • Monensin
  • Sodium
  • Potassium