Insulin and glucagon play the main parts in the process of glucose regulation. The purpose of insulin is to lower glucose levels following a meal. Glucagon is secreted between meals in order to release glucose into the blood stream. The balance is maintained and glucose levels are normally stable. However, in the case of diabetes, hormonal interactions are not well-balanced.
Relatively uninvestigated hormone
Lena Eliasson, scientist at LUDC in Malmö, says “Patients with diabetes have an insufficient insulin release and/or decreased sensitivity to insulin at the target tissue. In addition, many diabetics also have raised levels of glucagon, which exaggerate the already high glucose levels”. Lena Eliasson is one of the authors of an article which is now being published in the journal Cell Metabolism. In this article, the role of various hormones in the regulation of glucagon is discussed.
“Glucagon is a relatively uninvestigated hormone. This is surprising, not least relating to diabetes, as it is very important in its capacity as the body’s main hormone for raising glucose levels,” says Yang De Marinis, one of the other main authors of the article.
Other important hormones
In the article, the authors studied mice to learn how the secretion of glucagon from cells is regulated. Among other things, they show that there are other important hormones at play in addition to insulin and glucagon. One such hormone is the gut hormone GLP-1, which stimulates the secretion of insulin and inhibits the secretion of glucagon. These properties have resulted in the use of substances similar to GLP-1 as medication in the treatment of type 2 diabetes.
“We have studied how things work at a cellular level when GLP-1 inhibits glucagon and stimulates insulin. We have then compared this with the stress hormone adrenalin, which has the opposite effect,” says Yang De Marinis, and goes on to note that both hormones use the same biological signal pathway but with a slight difference, which causes them to have the opposite effect in cells that secrete glucagon.
Maintaining the balance
The effects of the hormones are logical. When we eat, GLP-1 inhibits the release of glucagon, which raises glucose levels, as the body does not require the additional glucose. At the same time, GLP-1 stimulates the secretion of insulin that deals with glucose derived from the food. It is also logical that the stress hormone adrenalin lowers insulin levels and increases the secretion of glucagon. In stressful situations, it is essential for the body that the glucose levels do not drop too low. “This is important because the brain needs glucose to think rationally and our cells need energy to enable us to move quickly, running away from danger, for example.”
Text: Tord Ajanki/Camilla Franks
The study has been published in the journal Cell Metabolism