TABLE 1.

Influence of an ATP-depleting treatment and monensin on cellular accumulation of azithromycin in control J774 macrophages and in J774 macrophages exposed to verapamila

Treatment% Cellular accumulationb
Control cellsCells exposed to verapamil
Control100.0 ± 7.8287.6 ± 20.4
ATP depletionc254.4 ± 30.7310.7 ± 33.9
Monensin5.9 ± 1.03.4 ± 0.6
  • a ATP depleting treatment was for 90 min, monensin (20 μM) treatment was for 3 h, azithromycin was used at a concentration of 5 mg/liter, and verapamil was used at a concentration of 20 μM. By statistical analysis (one-way analysis of variance), P was <0.001 for control cells versus cells exposed to verapamil for the control treatment, the control treatment versus ATP depletion for control cells, and the control treatment versus monensin depletion for control cells.

  • b Percentage of the cellular accumulation observed in cells without any treatment (azithromycin alone). Data are the means ± standard deviations of three experiments.

  • c ATP depletion was obtained by 1 h of preincubation in the presence of 60 mM 2-deoxyglucose and 5 mM NaN3; these conditions were maintained during the incubation with azithromycin.