Pig bile powder maintains blood glucose homeostasis by promoting glucagon-like peptide-1 secretion via inhibiting farnesoid X receptor

Figure 2 Bile powder alleviated hyperglycemia through glucagon-like peptide-1 signaling. A: Schematic diagram. Mice were fed a high-fat diet (HFD) for 6 weeks and were injected with streptozotocin (STZ) (50 mg/kg, intravenous) to induce blood glucose disorder. The HFD was continued for an additional 6 weeks. The mice were randomly divided into three groups (n = 5 per group): The HFD + STZ group; the bile powder (BP) group (75 mg/kg/day BP, intragastric gavage); and the BP + glucagon-like peptide-1 receptor agonist group [75 mg/kg/day BP, intragastric gavage + 25 nmol/kg/day glucagon-like peptide-1 receptor antagonist, exendin-3 (3-39) amide, intraperitoneal]. The oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed after the 30-day treatment; B: OGTT; C: Area under the curve (AUC) of the OGTT after the 30-day treatment; D: ITT; E: AUC of the ITT after the 30-day treatment. Data are shown as mean ± SEM. P < 0.05 compared between groups. Statistical analysis was performed using the Student’s t-test. ^aP < 0.05. ¹High-fat diet-streptozotocin vs bile powder. ²Bile powder vs bile powder + glucagon-like peptide-1 receptor antagonist. HFD: High-fat diet; STZ: Streptozotocin; BP: Bile powder; OGTT: Oral glucose tolerance test; ITT: Insulin tolerance test; AUC: Area under the curve; GLP-1: Glucagon-like peptide-1; GLP1-RA: Glucagon-like peptide-1 receptor antagonist.