Fig. 1.

Proliferation of NRK and INS-1 cells cultured under 3% and 20% oxygen tensions. Cells were seeded 1 × 10⁴ cells/60 mm dish and the cell number was then counted at the indicated times. Means of three experiments are shown. Closed square, 20% O₂; open square, 3% O₂ (± SEM indicated by error bars).