Fig. 1. ATP depletion and cell survival during hypoxia in renal cell carcinoma. Caki-1 cells were exposed to 1% O₂ and ATP content was measured for up to 120 minutes using a luciferase assay (A). The cytotoxicity of hypoxia was measured by cleavage of WST-1 in formazan by spectrophotometry (B). ATP levels and cytotoxicity during hypoxia are represented as the percentage values relative to normoxia. Means ± s.e.m. are given for three separate experiments.