**3. Results**

#### *3.1. E*ff*ects of Pravastatin on Hepatic Mitochondrial Respiration*

The lowest concentration of pravastatin (100 μM) did not affect the mitochondrial respiration in the liver. Pravastatin in higher concentrations (300 μM and 1000 μM) reduced state 3 (complex I: pravastatin 300 μM: 77.5% ± 3.2%\*, pravastatin 1000 μM: 60.7% ± 5.3%\*; complex II: pravastatin 300 μM: 84.8% ± 2.4%\*, pravastatin 1000 μM: 72.3% ± 6.2%\*) (Figure 1A,D) and RCI (complex I: pravastatin 300 μM: 75.3% ± 5.0%\*, pravastatin 1000 μM: 66.4% ± 4.2%\*, complex II: pravastatin 300 μM: 82.6% ± 6.1%\*, pravastatin 1000 μM: 72.2% ± 5.9%\*) (Figure 1B,E) for both complexes without changing the ADP/O-ratio (Figure 1C,F).

**Figure 1.** Effect of pravastatin (100 μM, 300 μM and 1000 μM) on hepatic mitochondrial respiration: State 3 for complex I (**A**) and II (**D**), respiratory control index (RCI) for complex I (**B**) und II (**E**) and ADP/O ratio for complex I (**C**) and II (**F**). Data are presented as mean ± standard deviation (S.D.), *n* = 7–8, \* *P* < 0.05 vs. control, *P* < 0.05 between groups.

#### *3.2. E*ff*ects of Pravastatin on Colonic Mitochondrial Respiration*

The lowest concentration of pravastatin (100 μM) did not affect the mitochondrial respiration in the colon. Pravastatin in middle concentration (300 μM) reduced state 3 for complex II (86.1% ± 4.8%\*) (Figure 2D) and in high concentration (1000 μm) decreased state 3 for both complexes (complex I: 63.6% ± 8.2%\*, complex II: 77.3% ± 4.1%\*) (Figure 2A,D).

**Figure 2.** Effect of pravastatin (100 μM, 300 μM and 1000 μM) on colonic mitochondrial respiration: State 3 for complex I (**A**) and II (**D**), respiratory control index (RCI) for complex I (**B**) und II (**E**) and ADP/O ratio for complex I (**C**) and II (**F**). Data are presented as mean ± S.D., *n* = 7–8, \* *P* < 0.05 vs. control, *P* < 0.05 between groups.

The RCI in colonic mitochondria was decreased only by pravastatin at the highest concentration (1000 μM) and only for complex II (83.8 ± 12.6%\*) (Figure 2E).

Pravastatin in high concentration (1000 μM) increased the ADP/O-ratio for both complexes (complex I: 151.5% ± 50.4%\*, complex II: 136.4% ± 24.9%\*) (Figure 2C,F).

#### *3.3. E*ff*ects of Gemfibrozil on Hepatic Mitochondrial Respiration*

Similarly to pravastatin, gemfibrozil in low concentration (100 μM) did not affect the mitochondrial respiration in the liver. Gemfibrozil at higher concentrations (300 μM and 1000 μM) reduced state 3 (complex I: gemfibrozil 300 μM: 56.9% ± 5.5%\*, gemfibrozil 1000 μM: 24.4% ± 2.5%\*; complex II: gemfibrozil 300 μM: 87.8% ± 18.5%\*, gemfibrozil 1000 μM: 50.9% ± 11.4%\*) (Figure 3A,D) and RCI (complex I: gemfibrozil 300 μM: 45.1% ± 5.2%\*, gemfibrozil 1000 μM: 21.5% ± 2.8%\*, complex II: gemfibrozil 300 μM: 70.4% ± 5.5%\*, gemfibrozil 1000 μM: 37.8% ± 8.3%\*) (Figure 3B,E) for both complexes. Gemfibrozil 300 μM reduced ADP/O for complex I (81.5% ± 7.6%\*) (Figure 3C). ADP/O-ratio after treatment with gemfibrozil 1000 μM was significantly higher than ADP/O-ratio in other gemfibrozil-groups.

**Figure 3.** Effect of gemfibrozil (100 μM, 300 μM and 1000 μM) on hepatic mitochondrial respiration: State 3 for complex I (**A**) and II (**D**), respiratory control index (RCI) for complex I (**B**) und II (**E**) and ADP/O ratio for complex I (**C**) and II (**F**). Data are presented as mean ± S.D., *n* = 7–8, \* *P* < 0.05 vs. control, *P* < 0.05 between groups.

#### *3.4. E*ff*ects of Gemfibrozil on Colonic Mitochondrial Respiration*

Gemfibrozil in low concentration (100 μM) reduced state 3 for complex I (89.3% ± 5.5%\*). Gemfibrozil at the middle concentration (300 μM) did not show any effect on colonic mitochondrial respiration. Gemfibrozil at high concentration (1000 μM) reduced state 3 for both complexes (complex I: 80.8% ± 6.6\*, complex II: 92.5% ± 15.2%\*) and increased the ADP/O-ratio for complex I (133.8% ± 33.8%\*) without changing the RCI (Figure 4B,E).

**Figure 4.** Effect of gemfibrozil (100 μM, 300 μM and 1000 μM) on colonic mitochondrial respiration: State 3 for complex I (**A**) and II (**D**), respiratory control index (RCI) for complex I (**B**) und II (**E**) and ADP/O ratio for complex I (**C**) and II (**F**). Data are presented as mean ± S.D., *n* = 7–8, \* *P* < 0.05 vs. control, *P* < 0.05 between groups.
