Incretins are metabolic hormones produced in the gut in response to food moving down the digestive system. The two main incretins produced are Glucagon Like Peptide – 1 (GLP-1) and Glucose-dependent insulinotropic polypeptide (GIP).
Background
Glucagon Like Peptide (GLP) hormones were first introduced to the world in a paper published in 1982, where researchers revealed that they had discovered two new hormones in the intestines. In 1983 another group of researchers identified these two new hormones as GLP-1 and GLP-2.
It was later found that GLP-1 could stimulate insulin production. This discovery was important as earlier research on GIP, had suggested that other substances in the intestines beside GIP could stimulate insulin production. In 1987 a paper published in the Lancet a scientific journal, confirmed that GLP-1 is a hormone in humans that can stimulate insulin release from the pancreas.
Glucose-dependent insulinotropic polypeptide (GIP) was the first to be identified in the late 1960’s as an enterogastrone, a hormone that stops the production of stomach juices and slows down the movement of food from the stomach. With continuous research its role as an incretin became more prominent and the classification was changed.
How do incretins work?
Incretins are hormones. Hormones are chemical messengers that carry messages to different organs in the body to produce a desired effect. In the case of incretins food moving down the digestive tract trigger their production and release by the small intestines. They are then transported into the bloodstream and act on the pancreas, stomach and the brain.
In the pancreas they stimulate β-cell to release insulin, while at the same time telling the α-cells of the pancreas to stop releasing glucagon. The balance between glucagon and insulin is important for blood glucose control. In type 2 diabetes this delicate balance is often affected resulting in high blood sugar levels.
In the stomach Incretins delay the movement of food out of the stomach, causing food to stay longer in the stomach, making one feel fuller for longer. Food staying longer in the stomach helps control the amount of glucose released into the bloodstream.
In the brain incretins work on the part of the brain that controls appetite as well as feelings of hunger and fullness. They suppress appetite making one feel satisfied for longer.
Incretins once released into the blood stream lasts for less than 2 minutes in the body. They are quickly broken down by a substance or enzyme called dipeptidyl peptidase-4 (DPP 4).
Importance of incretins in medicine today and beyond.
Medications called GLP-1 Agonists that mimic the effect of incretins in the body have been developed for use in the treatment of type 2 diabetes. Due to their effect on the stomach and appetite these medications have been shown to cause weight loss, and some have been approved for use in the treatment and management of obesity.
Medications that block DPP 4 from breaking down incretins have also been developed and approved for the treatment of type 2 diabetes. They are referred to as DPP 4 inhibitors.
Research is ongoing on the possible use of incretin-based medications in the treatment of other diseases, other than type 2 diabetes.
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Thank you Mbali for your article. I believe its important for us to teach our patients to know their medication and also have honest conversations with their health care advisors. Many patients wanted the benefit of losing weight without putting in the work. This has potential of causing a few complications including interaction with other medication and diseases.
Keep on doing great work
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