Glucagon-like peptide-1 (GLP-1) is a peptide hormone primarily produced by intestinal L cells and belongs to the group of incretins. Here is a detailed introduction about it:

Physiological Functions

• Blood Glucose Regulation

• Promoting Insulin Secretion: GLP-1 acts on pancreatic islet β cells in a glucose-dependent manner, promoting the synthesis and secretion of insulin. When blood glucose levels rise, GLP-1 secretion increases, stimulating insulin release and thus reducing blood glucose.

• Inhibiting Glucagon Secretion: It can reduce the secretion of glucagon from pancreatic islet α cells, thereby decreasing glycogenolysis in the liver and gluconeogenesis, and lowering blood glucose levels.

• Gastrointestinal Regulation

• Delaying Gastric Emptying: GLP-1 can inhibit gastrointestinal motility and gastric juice secretion, delaying the emptying of gastric contents. This prolongs the residence time of food in the stomach, reducing the rapid rise in postprandial blood glucose.

• Reducing Appetite: By acting on the central nervous system, it generates a feeling of satiety, reduces food intake, and decreases appetite.

• Other Functions

• Promoting β Cell Proliferation and Inhibiting Apoptosis: It stimulates the proliferation and differentiation of pancreatic islet β cells and inhibits the apoptosis of islet β cells, which helps maintain the number and function of islet β cells and plays a protective role in islet function.

• Improving Blood Lipids and Blood Pressure: Some studies have shown that GLP-1 has the effect of improving the blood lipid profile. It can reduce the levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol in patients with type 2 diabetes to varying degrees. It can also lower the systolic blood pressure of patients with type 2 diabetes.

Clinical Applications

• Treatment of Type 2 Diabetes Mellitus: GLP-1 receptor agonists, as analogs of GLP-1, have been widely used in the treatment of type 2 diabetes. Examples include liraglutide, semaglutide, dulaglutide, etc. They can be used alone or in combination with drugs such as metformin, sulfonylureas, and basal insulin to effectively reduce blood glucose levels with a relatively low risk of hypoglycemia.

• Treatment of Obesity: GLP-1 receptor agonists can lead to weight loss through effects such as delaying gastric emptying, reducing appetite, and increasing satiety. They are suitable for obese individuals (BMI ≥ 30 kg/m²) and overweight individuals (BMI ≥ 27 kg/m² with at least one obesity-related complication).

• Cardiovascular Protection and Potential Renal Benefits: Some GLP-1 receptor agonists, such as liraglutide, semaglutide, tirzepatide, Retatrutide and dulaglutide, have clear cardiovascular protective effects and can also bring potential renal benefits. They can reduce the risk of cardiovascular diseases and are beneficial for patients with type 2 diabetes who have comorbid cardiovascular or kidney diseases.