Table 4.

Effects of hypoxia and bed rest on glutathione redox capacity in erythrocytes (RBC) and in whole blood (WB).

	Ambulatory		Bed rest		P
	Normoxia	Hypoxia	Normoxia	Hypoxia	Bed rest effect	Hypoxia effect	Interaction
Hematocrit (percent)	46 ± 1	51 ± 1	47 ± 1	51 ± 1	0.20	<0.001	0.12
Total glutathione (μmol/L RBC)	2692 ± 84	2620 ± 79	2617 ± 105	2547 ± 86	0.07	0.21	0.34
Total glutathione (μmol/L WB)	1245 ± 49	1331 ± 52	1236 ± 54	1287 ± 51	0.22	0.01	0.45
GSH/GSSG1 (ratio)	137 ± 26	213 ± 34*	207 ± 41	176 ± 36	0.93	0.52	0.02
GSSG (μmol/L RBC)	32 ± 9	19 ± 5*	21 ± 5	38 ± 20	0.87	0.43	0.02
GSSG (μmol/L WB)	15 ± 4	9 ± 2	10 ± 2	19 ± 10	0.89	0.76	0.02
Glutathione FSR2 (percent/day)	25 ± 4	38 ± 6	35 ± 3	41 ± 3	0.09	0.03	0.21
Glutathione ASR3 (μmol/day/L RBC)	669 ± 122	990 ± 143	898 ± 82	1053 ± 88	0.10	0.02	0.19
Glutathione ASR (μmol/day/L WB)	306 ± 55	493 ± 69	420 ± 40	524 ± 41	0.23	0.02	0.27
GCL-C4 (fraction of GAPDH5)	0.63 ± 0.09	1.01 ± 0.25	0.64 ± 0.10	0.85 ± 0.14	0.96	0.03	0.91
GCL-M6 (fraction of GAPDH)	0.82 ± 0.15	1.29 ± 0.14	0.87 ± 0.13	1.05 ± 0.12	0.74	0.05	0.27

Data are expressed as mean ± SEM. Data were analyzed with the use of a 2-factor repeated measure ANOVA or ANCOVA. Post hoc analysis was performed using Student t-test with Bonferroni correction. ^∗p < 0.05 hypoxia versus normoxia. ¹GSH/GSSG, ratio between reduced and oxidised glutathione. ²FSR, fractional synthesis rate; ³ASR, absolute synthesis rate; ⁴GCL-C, glutamate cysteine ligase– catalytic subunit; ⁵GAPDH, glyceraldehyde-3-phosphate dehydrogenase; ⁶GCL-M, glutamate cysteine ligase–modulator subunit.