4.2. Describe the function of glucagon

This guide will help you answer 4.2. Describe the function of glucagon.

Glucagon is a hormone produced by the pancreas, a gland located behind the stomach. It is vital for maintaining the balance of glucose in the blood. Glucagon works alongside insulin, another hormone from the pancreas, to keep blood sugar levels stable. While insulin lowers blood sugar, glucagon has the opposite effect; it raises blood sugar levels when they drop too low.

This balance is essential for normal body functioning as glucose is the primary source of energy for the body’s cells. Without the right amount of glucose in the blood, the body cannot function properly, and this can lead to serious health problems.

Where Glucagon Comes From

Glucagon is produced in specialised cells of the pancreas called alpha cells. These cells are located in small clusters known as the islets of Langerhans. The pancreas monitors blood sugar levels constantly. When those levels fall below a certain point, the alpha cells release glucagon into the bloodstream.

How Glucagon Works

Glucagon’s main role is to increase blood sugar levels when they become too low. It achieves this by acting on the liver, which is the body’s primary storage site for glucose. Glucose in the liver is stored in the form of glycogen, a complex carbohydrate that can be readily broken down into glucose when needed.

When glucagon is released into the bloodstream, it signals the liver to:

• Break down glycogen into glucose, which is then released into the bloodstream (a process called glycogenolysis).
• Create new glucose from non-carbohydrate sources like amino acids and fats (a process called gluconeogenesis), if glycogen stores are low or depleted.

These processes quickly increase blood sugar levels, ensuring the body has enough energy to function.

What Triggers Glucagon Release?

Glucagon secretion is primarily triggered by low blood sugar levels (a condition known as hypoglycaemia). Hypoglycaemia can occur for several reasons, such as fasting, skipping meals, intense exercise, or certain medical conditions.

In addition to low blood sugar, glucagon release can also be stimulated by:

• High levels of amino acids in the blood, which happen after eating a protein-rich meal.
• Stress or trauma, which activates the “fight or flight” response and increases the demand for energy.

Once blood sugar levels return to normal, the pancreas stops releasing glucagon, ensuring that blood sugar doesn’t rise too high.

The Relationship Between Glucagon and Insulin

Glucagon works in tandem with insulin to maintain blood sugar balance. While glucagon raises blood sugar, insulin has the opposite role—it lowers blood sugar by allowing cells to absorb glucose from the bloodstream.

After eating, blood sugar levels rise, prompting the pancreas to release insulin. Insulin helps move glucose into cells where it can be used for energy, or into the liver and muscles for storage as glycogen. Once blood sugar levels drop back to normal, insulin secretion slows down.

When blood sugar levels become too low, the pancreas releases glucagon. This releases glucose from the liver, bringing blood sugar levels back to normal.

This interplay between glucagon and insulin keeps blood sugar levels within a healthy range, preventing both hypoglycaemia (low blood sugar) and hyperglycaemia (high blood sugar).

The Importance of Glucagon in the Body

Glucagon plays a key role in keeping the body energised, especially during times when food intake is limited or energy demands increase. Without glucagon, the body would struggle to raise blood sugar levels during fasting or physical exertion, which could lead to symptoms like fatigue, confusion, and even seizures in severe cases.

In people with diabetes, this balance between insulin and glucagon is often disrupted. For those with type 1 diabetes, the pancreas may not produce insulin at all, while in type 2 diabetes, the body may not respond properly to insulin. This can result in ongoing high blood sugar levels.

At the same time, people with diabetes are also at higher risk of hypoglycaemia, either due to medications or other factors. In emergencies, an injection of glucagon can be used to treat severe hypoglycaemia.

Medical Use of Glucagon

In healthcare settings, glucagon is an important tool for managing hypoglycaemia in people with diabetes. Hypoglycaemia can occur when blood sugar levels drop too low, either from skipping meals, taking too much insulin, or engaging in strenuous activities.

If a person becomes unconscious or is unable to eat something to raise their blood sugar, a glucagon injection can be given. The injection stimulates the liver to release glucose, raising blood sugar quickly. This can be life-saving in severe situations.

Glucagon is available in pre-filled injection kits or nasal sprays, making it easy to administer during emergencies. Family members, carers, or even colleagues should know how to use these if they’re around a person with diabetes.

Other Functions of Glucagon

In addition to its role in managing blood sugar, glucagon affects other processes in the body:

• Lipid Metabolism: Glucagon can help break down fat stores to be used for energy when blood sugar is low.
• Heart Function: Glucagon can improve the strength of the heart’s contractions. This makes it a potential treatment option during certain heart emergencies.

However, the main and most significant role of glucagon remains its ability to raise blood sugar levels during hypoglycaemia.

What Happens When Glucagon Fails?

If the pancreas does not produce enough glucagon, or if the liver does not respond to it, severe hypoglycaemia can occur. This can result in symptoms such as:

• Shaking
• Sweating
• Confusion
• Loss of consciousness
• Seizures

In such cases, medical attention is required immediately. Repeated hypoglycaemic episodes can also cause long-term damage to the brain and other organs, as they rely on glucose for proper functioning.

For people with diabetes, glucagon production may be impaired due to damage to the pancreas. This is why it’s important for them to monitor blood sugar levels and have an emergency glucagon treatment available.

Final Thoughts

To summarise, glucagon is a hormone produced by the pancreas. Its primary function is to prevent blood sugar levels from falling too low by triggering the release of glucose from the liver. This plays a crucial role in maintaining energy supply to the body, especially during fasting or physical activity.

Understanding how glucagon works is essential when supporting individuals with diabetes, as it highlights the importance of emergency treatment for hypoglycaemia. Having knowledge of this can help health and social care workers respond quickly and appropriately in challenging situations.