GPBA Receptors
GPBA receptors (TGR5, GPBAR1, M-BAR) are G protein-coupled receptors (GPCRs) that are activated by bile acids. They are highly expressed in the gallbladder, ileum and colon, and are important in the regulation of glucose and lipid metabolism, and energy utilization.
GPBA Receptor Agonists |
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Cat. No. | Product Name / Activity |
3906 | Betulinic acid |
Antitumor and anti-HIV agent; GPBA receptor (TGR5) agonist; also activates NF-κB | |
4478 | GPBAR-A |
GPBA receptor (TGR5) agonist | |
5129 | TC-G 1005 |
Potent and selective GPBA receptor (TGR5) agonist |
GPBA receptors (GPBAR1, M-BAR, TGR5) are G protein-coupled receptors (GPCRs) that are activated by bile acids. They are primarily expressed in the gallbladder, ileum and colon, and are important in the regulation of glucose and lipid metabolism, and energy expenditure.
GPBA receptors are members of the class A (rhodopsin-like) subgroup of GPCRs and are present at varying levels in the liver, gallbladder, ileum, colon, heart, spleen, kidney, placenta, leukocytes, skeletal muscle, brown adipose tissue and central nervous system. Bile acids, which are the major constituent of bile, are endogenous ligands for the GBPA receptor. They are synthesized from cholesterol in the liver and are stored in the gallbladder. Bile acids are secreted into the duodenum where they promote the absorption of lipids and lipid-soluble vitamins.
The receptors are involved in a range of processes. Activation of GPBA receptors increases energy consumption in mouse brown adipose tissue and human skeletal muscle cells by promoting the conversion of inactive thyroxine (T4) to active 3,5,3'-tri-iodothyronine which, in turn, enhances mitochondrial oxidative phosphorylation. Another effect of GBPA activation is on glucose metabolism. Bile acids released into the gut following ingestion of a meal, activate GBPA receptors on enteroendocrine cells resulting in the release of glucagon-like peptide (GLP-1) into the blood, which in turn regulates insulin secretion from pancreatic β cells and glucose homeostasis. In addition, GBPA receptors are expressed on macrophages where their activation suppresses NF-κB signaling and inhibits production of pro-inflammatory cytokines, which has been proposed to attenuate the development of atherosclerosis.