I. Engstrom et al., EFFECTS OF THE IONOPHORE GRAMICIDIN-D ON ENERGY-METABOLISM IN HUMAN ERYTHROCYTES, Scandinavian journal of clinical & laboratory investigation, 53(3), 1993, pp. 247-252
Washed human erythrocytes were incubated in phosphate-buffered saline
at 37-degrees-C with different concentrations (2-80 mg l-1) of the mon
ovalent cationophore gramicidin D. The ionophore induced a decrease of
ATP content and energy charge (EC) and a concomitant increase in ADP
and AMP contents. At a concentration of 10 mg l-1 of the ionophore the
reduction of EC and ATP concentration was about 50%. Increasing the c
oncentration of the ionophore resulted in a substantial haemolysis wit
h no further effect on the nucleotide levels. Lowering the concentrati
on of the ionophore to 5 mg l-1 (to avoid haemolysis) lead to a simila
r effect on the energy status. Ouabain at 0.5 mmol l-1 in incubation m
edium distinctly blunted the ionophoric effect on EC and adenine nucle
otides. Addition of glucose on the contrary reversed these effects by
about 80%. Hence, the glucose-induced increase in glycolytic flux as e
videnced by an increase in lactate production was not sufficient to re
store energy state.