Glucagon-like peptide-1 (GLP-1) is a hormone that is secreted in your intestines when you eat. It affects the gut, liver, and pancreas, and it plays a number of important roles, including increasing insulin secretion from the pancreas and telling your brain you are full.

Recently, researchers have been examining GLP-1 as a potential treatment for diabetes.

How is GLP-1 important in the treatment of diabetes?

Doctors identify the progression of type 2 diabetes by a marked decline in insulin levels, incretin (gastrointestinal) effect, and beta-cell function. GLP-1 therapy targets the GLP-1 receptors on the surface of beta cells, stimulating insulin secretion and restoring the incretin effect. These hormones make effective targets when treating type 2 diabetes because they help regulate insulin, glucose, and gastric emptying.

Targeting GLP-1 activity can be done in two ways:

  1. Directly, by activating the GLP-1 receptors.

  2. Indirectly, by inhibiting the DPP-4 enzyme from breaking down GLP-1.

What are GLP-1 receptor agonists?

Within minutes of eating, GLP-1 receptor agonists (GLP-1RA) mimic the action of the naturally occurring GLP-1 peptide that is normally released after a meal.

These receptor agonists are known to stimulate the release of insulin, suppress glucagon secretion, and slow gastrointestinal motility. All three mechanisms contribute to the lowering of blood glucose in the presence of hyperglycemia. Glucagon-like peptide (GLP) agonists bind to a membrane GLP receptor. As a consequence, pancreatic beta cells release more insulin.

Combination therapy with insulin and GLP-1RA

Recent studies have demonstrated that the combination therapy of GLP-1RA and basal insulin offers advantages over traditional combination therapy with metformin, such as:

Additional lowering of A1c (average blood sugar level over the past two to three months), without a major risk for hypoglycemia;

Lower basal insulin requirements;

Decreased postprandial glucose levels (with or without fasting plasma glucose decreases); and

Weight loss (or, at the very least, less weight gain).

Types of GLP-1RAs

The U.S. Food and Drug Administration has approved different types of GLP-1RAs for use with insulin.You may have heard of these:

Exenatide
Liraglutide

Concerns

There are two major concerns for you to consider when it comes to using GLP-1RAs: gastrointestinal side effects (nausea, vomiting, and diarrhea) and the high cost. Talk with your doctor to see if combination therapy, GLP-1RA and insulin, is the right choice for managing your diabetes.

Sources:
- GLP-1 as a Target of Type 2 Diabetes Treatment
- Peptide Analogs