Enzymatic activities of the respiratory chain complexes in skeletal muscle
| . | Muscle biopsy 3 mo after ATO treatment withdrawal . | Muscle biopsy 6 mo after ATO treatment withdrawal . | Controls (n = 40) . |
|---|---|---|---|
| Enzymatic activities | |||
| Complex I | 11.7 | 14.0 | 14.1 (9.7-21.3) |
| Complex II + III | 2.9* | 4.0* | 7.0 (4.6-12.7) |
| Complex II | 12.0 | 13.7 | 16.8 (11.7-21.4) |
| Complex III | 109.3 | 130.4 | 125.8 (79.9-165.5) |
| Complex IV | 45.3* | 60.6* | 86.7 (71.0-116.7) |
| Citrate synthase | 104.5 | 115.5 | 166.3 (89.6-334.0) |
| Activity ratios | |||
| I/II + III | 4.03* | 3.50* | 2.01 ± 0.54 |
| I/III | 0.11 | 0.11 | 0.11 ± 0.02 |
| I/IV | 0.26* | 0.23* | 0.16 ± 0.02 |
| II/IV | 0.26* | 0.23 | 0.19 ± 0.04 |
| III/IV | 2.41* | 2.15* | 1.45 ± 0.27 |
| IV/II + III | 15.62 | 15.15 | 12.39 ± 3.12 |
| . | Muscle biopsy 3 mo after ATO treatment withdrawal . | Muscle biopsy 6 mo after ATO treatment withdrawal . | Controls (n = 40) . |
|---|---|---|---|
| Enzymatic activities | |||
| Complex I | 11.7 | 14.0 | 14.1 (9.7-21.3) |
| Complex II + III | 2.9* | 4.0* | 7.0 (4.6-12.7) |
| Complex II | 12.0 | 13.7 | 16.8 (11.7-21.4) |
| Complex III | 109.3 | 130.4 | 125.8 (79.9-165.5) |
| Complex IV | 45.3* | 60.6* | 86.7 (71.0-116.7) |
| Citrate synthase | 104.5 | 115.5 | 166.3 (89.6-334.0) |
| Activity ratios | |||
| I/II + III | 4.03* | 3.50* | 2.01 ± 0.54 |
| I/III | 0.11 | 0.11 | 0.11 ± 0.02 |
| I/IV | 0.26* | 0.23* | 0.16 ± 0.02 |
| II/IV | 0.26* | 0.23 | 0.19 ± 0.04 |
| III/IV | 2.41* | 2.15* | 1.45 ± 0.27 |
| IV/II + III | 15.62 | 15.15 | 12.39 ± 3.12 |
The first muscle biopsy was performed 3 months after ATO treatment withdrawal and demonstrated a partial decrease in enzymatic activities of the respiratory chain complexes IV and II + III. The second biopsy was performed 6 months after ATO treatment was interrupted and showed improved activities of all the respiratory chain complexes. Complex enzymatic activities are measured in an 800g supernatant of crude muscle homogenates. Enzymatic activities are expressed as nanomoles per minute per milligram of protein and normalized with respect to the citrate synthase activity. Control enzymatic activities are given as mean (range), and control values of activity ratios are given as mean ± SD. Activity ratios reflect the balance between complex activities required for optimum function of the respiratory chain.
Abnormal value.