Figure 1. Adenosine (Ade) increases intracellular ATP contents in multiple cells.

(A) Primary thymocytes were exposed to either vehicle DMSO (DM) or Ade in normal culture medium for 4 h and cells were collected for total ATP assay by HPLC (LC-6AD; Shimadzu). ATP contents (µM) of equal number of cells (2×10⁵) were compared (n = 4). Each column represents the average of independent repeated experiments. Mean ±SD. *p<0.05 compared to controls. (B) K562 cells were treated with indicated doses of Ade or oligomycin (Oli; 1 µg/ml) in the absence of d-glucose in RPMI 1640 medium for 6 h. d-glucose (2 g/L) was used as a positive control. Mean ±SD (n = 4). *p<0.05 vs. control; ^#p<0.05 vs. Oli treatment alone. (C) K562 was exposed to 2 mM of Ade for 0.5, 2, and 6 h in the absence of d-glucose in the culture medium. Mean ±SD. *p<0.05 vs. 0.5 h treatment. (D) Increase of ATP in multiple cell lines: A549, MCF7, and Hela cells were exposed to either DMSO or 2 mM of Ade for 6 h in the absence (G-) or presence of d-glucose (2 g/L, G+) in the culture medium. ATP contents were detected by HPLC (n = 4) and the increase of ATP after Ade treatment was calculated as: Ade-treated/vehicle-treated. All controls were set as 1.0.