EVIDENCE OF SODIUM-DEPENDENT GLUCOSE TRANSPORT IN HUMAN ERYTHROLEUKEMIA CELLS

摘要

Sodium-dependent transport of D-glucose has been reported only in epithelial cells of small intestine and kidney, and well-differentiated tumors thereof. We observed a two-fold decrease (p < 0.05) in the intracellular distribution volume (V'(ic) defined as steady-state intracellular uptake extracellular concentration) of the non-metabolized D-glucose analog 3-O-methylglucose (3-O-MG) when logarithmically growing K562 cells (an anaplastic human erythroleukemia) were incubated 3 h in choline-substituted, phosphate buffered saline (PBS) rather than Na+ PBS, each containing a glucose concentration ([Glu]) of 5.6 mM. Electromechanically measured cellular volume V-c differed < 10% between the different media. in Na+ PBS, V'(ic)(3-O-MG) was approximately twice V, and declined progressively when [Glu] was reduced to 2.8 and 0.1 mM. We conclude that, in a balanced salt medium containing glucose as the only energy source, K562 cells express a concentrative mechanism having characteristics consistent with Na+-dependent transport of glucose. [References: 24]