Cation transport and its altered regulations in human stomatocytic erythrocytes
Abstract:
Cation transport in a population of stomatocytic red blood cells (RBC) is abnormal in the following respects. First, active transport against a gradient, defined as the nonisotopic net accumulation of Na+ or loss of K+ induced by 0.1 mM ouabain, is markedly elevated (7.3 and 6.3 mEq/liter cells/hr for Na+ and K+, respectively), but the Na+:K+ active transport ratio is normal. Apparent uncoupling of the Na+ and K+ isotope transport is due to disproportionately increased ouabain-sensitive 24Na+-23Na+ exchange (32.7 mEq/liter cells/hr), which is measured as a portion of 24Na+ isotope efflux. Second, cation transport is unresponsive to variations in internal Na+ concentration but decreases with decreasing extracellular Na+.
Related Concept Videos
The Significance of Membrane Transport
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Membrane Transporters
Transporters are mainly composed of alpha-helices, built from bundles of ten or more helices traversing the plasma membrane. The solute-binding sites are located midway, where some of the helices are broken or distorted, making space for the binding site through...
ABC Transporters: Exporter
Transcellular Transport of Solutes
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters


