The drug Tirzepatide, which has been approved for diabetes treatment and is currently on the fast track for approval as a weight loss therapy, exerts its effects by uniquely activating two distinct mechanisms involved in insulin secretion and energy balance regulation, according to researchers at Duke Health.
Tirzepatide works by mimicking the GLP-1 and GIP hormones that are naturally secreted by the intestine after a meal, which prompts insulin secretion. It also reduces appetite by slowing down the time it takes the stomach to empty and interacting with areas in the brain harboring GLP-1 receptors to signal satiety.
Tirzepatide is marketed under the brand name Mounjaro. It and similar therapies are known as receptor agonists, meaning they bind to a certain receptor in cells, triggering a specific action for that cell to carry out. There is a long history of diabetes therapies that target the glucagon-like peptide-1 (GLP-1) receptor.
For people with type 2 diabetes, these GLP-1-based drugs restore insulin production and lower blood glucose. The therapies also make people who take the medication feel full longer and reduce appetite, which leads to people dropping weight over time. This has made GLP-1 based therapies very attractive for the treatment of diabetes and obesity.
Tirzepatide is unique in this class of drugs, in that it targets not only the GLP-1 receptor, but also an additional receptor for the glucose-dependent insulinotropic polypeptide (GIP). In theory, this additional receptor gives the drug a broader range of activity inside the body.
They also found that tirzepatide stimulated the production of glucagon, another islet hormone. GIP stimulates glucagon secretion, while GLP-1 inhibits it. The finding that tirzepatide stimulates glucagon secretion is more evidence that this drug has important activity at the GIP receptor.
