What Is a Glucagon Receptor?

Cheryl Bade
Cheryl Bade
Most diabetic patients need to receive daily insulin injections to control their blood glucose levels.
Most diabetic patients need to receive daily insulin injections to control their blood glucose levels.

A glucagon receptor is a G protein-coupled receptor found mainly in the liver. These receptors bind to the hormone glucagon made by the pancreas, and they cause the break down of glycogen, a storage form of sugar. Together, the hormones glucagon and insulin control blood glucose levels. When blood glucose dips, glucagon is released and attaches to a glucagon receptor to increase glucose levels. Glucagon receptors have been found to be important for the health of liver cells, called hepatocytes.

Glucagon receptors are mainly found in the liver.
Glucagon receptors are mainly found in the liver.

The pancreas makes two hormones, insulin and glucagon. After a meal, when blood glucose levels are too high, beta cells in the pancreatic islets release insulin, which allows cells throughout the body to take up glucose for use in energy production. This then lowers blood glucose levels. Some of that glucose is taken into liver cells where it is converted to glycogen, a polysaccharide that stores glucose.

A pancreas that is not performing correctly may cause bloating and watery stools.
A pancreas that is not performing correctly may cause bloating and watery stools.

When blood glucose levels lower between meals, the alpha cells in the pancreatic islets release the hormone glucagon. Most of the glucagon receptors are located in the liver, so when they attach to glucagon, the glycogen that has been stored in the liver cells is broken down into glucose and released into the blood. Blood sugar levels then increase back to normal.

Prolonged high blood glucose may cause vision problems in diabetics.
Prolonged high blood glucose may cause vision problems in diabetics.

A glucagon receptor is in the G protein-coupled receptor family. The GCGR gene has been found to code for the glucagon receptor protein, and using this gene for research has aided in studying it. When glucagon attaches to the glucagon receptor, it triggers the coupling of G proteins and begins a cascade effect, producing cyclic adenine monophosphate (cAMP), and it causes a release of calcium in the cell. Besides the liver, glucagon receptors have been found in the kidneys, small intestines, brain, fat tissue and beta pancreatic cells. In beta cells, glucagon receptors likely cause the inhibition of insulin production by these cells.

After eating sugar, an individual's blood glucose levels spike.
After eating sugar, an individual's blood glucose levels spike.

Glucagon mainly affects glucose levels in the body, but it might also be involved in fasting metabolism, during which the body runs low on glucose and mainly uses fats for energy production. The presence of glucagon receptors in hepatocytes is involved in the proper metabolism of these cells. This would explain why properly working glucagon receptors might be important for hepatocyte and liver health. Mutations in the glucagon receptor might be linked to type II diabetes. This receptor is likely to be studied further because it does do more in the body than simply increase blood glucose levels.

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    • Most diabetic patients need to receive daily insulin injections to control their blood glucose levels.
      By: Dmitry Lobanov
      Most diabetic patients need to receive daily insulin injections to control their blood glucose levels.
    • Glucagon receptors are mainly found in the liver.
      By: peterjunaidy
      Glucagon receptors are mainly found in the liver.
    • A pancreas that is not performing correctly may cause bloating and watery stools.
      By: inesbazdar
      A pancreas that is not performing correctly may cause bloating and watery stools.
    • Prolonged high blood glucose may cause vision problems in diabetics.
      By: JackF
      Prolonged high blood glucose may cause vision problems in diabetics.
    • After eating sugar, an individual's blood glucose levels spike.
      By: librakv
      After eating sugar, an individual's blood glucose levels spike.
    • Changes in blood glucose levels may cause diabetic patients to experience fatigue.
      By: brankatekic
      Changes in blood glucose levels may cause diabetic patients to experience fatigue.