Effects of the Arrabidaea chica extract on energy metabolism in the rat liver

Figures & data

Figure 1.  Effects of the extract of Arrabidaea chica on the respiratory activity of isolated rat liver mitochondria driven by β-hydroxybutyrate (A) and succinate (B). Each data point is the mean ± SEM of 6 independent experiments. ⁺p < 0.05, **p < 0.01, *p < 0.001, ANOVA with Newman-Keuls test.

Table 1.  The action of the Arrabidaea chica extract on mitochondrial respiration driven by β-hydroxybutyrate and succinate in the presence and absence of exogenously added ADP.

	β-Hydroxybutyrate (n = 6)		Succinate (n = 6)
Extract (mg/ml)	ADP/O	RC	ADP/O	RC
0.0	3.00 ± 0.01	6.26 ± 0.73	1.82 ± 0.07	5.67 ± 0.28
0.25	2.89 ± 0.30	5.07 ± 0.51	1.69 ± 0.08	4.28 ± 0.24**
0.50	2.74 ± 0.22	4.62 ± 0.23^+	1.72 ± 0.07	3.65 ± 0.24^*
0.75	2.57 ± 0.25	3.97 ± 0.37**	1.83 ± 0.06	3.34 ± 0.16^*
1.00	2.75 ± 0.17	3.07 ± 0.21*	1.85 ± 0.07	2.53 ± 0.14^*
1.25	-	1.26 ± 0.17*	-	1.00^*

⁺p < 0.05; **p < 0.01; *p < 0.001, ANOVA with Newman-Keuls test.

Figure 2.  Effects of the extract of Arrabidaea chica on several membrane-bound enzymatic activities in rat liver mitochondria. (A) NADH-oxidase, succinate-oxidase activities and TMPD-ascorbate oxidation. (B) ATPase activity of coupled and uncoupled mitochondria. Each assay point represents the mean of 5-8 independent experiments and the bars are SEM. ⁺p < 0.05, **p < 0.01, *p < 0.001, ANOVA with Newman-Keuls test.

Figure 3.  Actions of the Arrabidaea chica extract on ATPase and glucose 6-phosphatase activities. Livers from fed rats were homogenized and subjected to differential centrifugation as described in Materials and methods. The microsomal fraction was used for glucose 6-phosphatase and ATPase assays. Initial rates were measured at various extract concentrations. The data points are the means of five determinations. Bars are standard errors of the mean, *p < 0.001, ANOVA with Newman-Keuls test.

Table 2.  Adenine nucleotide and glucose 6-phosphate contents of livers from fed rats in the presence and absence of the Arrabidaea chica extract.

Extract (mg/ml)	ATP μmol × (g liver)^−1	Glucose 6-phosphate μmol × (g liver)^−1
0	2.01 ± 0.05	0.20 ± 0.02
1.0	1.53 ± 0.06*	0.33 ± 0.02^+

⁺p < 0.05, ^*p < 0.001, ANOVA with Newman-Keuls test.

Figure 4.  Effects of the extract of Arrabidaea chica on metabolic fluxes in perfused livers isolated from fed rats. (A) Time course of the changes caused by the extract in glycogen catabolism and oxygen uptake. The extract (1.0 mg/ml) was infused at 10-30 min, as indicated by the horizontal bar. (B) Concentration dependence of the effects of the A. chica extract on glucose and lactate release and oxygen consumption. The experimental protocol was the same described for A. Each data point is the mean ± SEM of three experiments.

Figure 5.  Effects of the extract of Arrabidaea chica on metabolic fluxes in perfused livers isolated from fasted rats. (A) Time course of the changes caused by 1.0 mg/ml of extract in glucose production and oxygen uptake. Lactate (2 mM) and pyruvate (0.2 mM) were infused at 10–70 min and the extract at 30–50 min as indicated by the horizontal bars. (B) Concentration dependence of the effects of the A. chica extract on oxygen uptake and gluconeogenesis. The experimental protocol was the same described for A. Each data point is the mean ± SEM of four experiments.