Table 1.

Hypoxia changes the free cellular NAD⁺/NADH ratio

Treatment	Control	Hypoxia
Free NAD+/NADH ratio	727	153
Estimated NADH signal
No treatment	18	46
Pyruvate	6	20

H1299 cells were exposed to hypoxia, and the free cytoplasmic NAD⁺/NADH ratios were calculated as described in the text. Nuclear NADH is regulated by hypoxia and pyruvate in H1299 cells. The nuclear NAD(P)H fluorescence (the sum of the NADH and NADPH signals) was measured by two-photon microscopy. The nuclear NADH level was calculated by assuming the NADPH/NADH ratio is 4, as determined by Shigemori et al. (19). Thirty millimolar pyruvate decreased the nuclear NADH signal.