10-03-2022 / Endocrinology & Diabetes

Insulin and Glucagon Hormones

Glucagon and Insulin are 2 major hormones responsible for controlling blood glucose levels. Let's talk about their production, roles and concerned diseases.

Insulin and Glucagon Hormones
Neeraja HNeeraja H

Neeraja H

MBBS, Medical Doctor

Table of Content

Glucagon and Insulin Hormone

  • Both Glucagon and Insulin hormones are produced by the pancreas. The pancreas consists of endocrine cells called the Islets of Langerhans. There are different types of these islets: Alpha cells which produce Glucagon and the Beta cells which produce insulin Hormone.

  • Both glucagon and insulin hormones are concerned with maintaining an ideal blood sugar level. They are complementary hormones meaning that both have opposite actions in maintaining blood sugar levels.

  • This state of fine balance between glucagon and insulin is very important to maintain the ideal glucose levels and to avoid any complications. They work in tandem to maintain a steady metabolism in the body.

The Role of Glucagon and Insulin hormones

  • The human body runs on three basic fuels, which are fats, proteins, and glucose (carbohydrate). Among these, Glucose is considered as the most rapid source of energy as it is easily accessible and in an easily usable form when compared with others. When the human body is exerted in any way, it needs an abundant supply of Glucose.

  • Insulin and Glucagon work in sync to manage this glucose levels within the ideal range.

  • Glucagon is responsible for raising blood glucose levels and insulin is concerned with lowering blood sugar. But how do they actually carry out these complementary actions?

To understand how insulin and glucagon complement each other, we need to take a peek into the glucose metabolism in our body.

Glucose metabolism of the human body

Glucose metabolism of the human body
  • Carbohydrates are a major source of energy in the food consumed by a vast majority of people in the world.

  • But the carbohydrates taken via food are complex structures and need to be broken down into simpler forms to be digested properly and assimilated by the body. The simplest form of carbohydrates is a sugar called Glucose.

  • Blood sugar levels are a reflection of how well the glucose is utilised in the body as a source of energy.

What happens to glucose in the body?

  • Now that we have a basic idea of what glucose actually is, let's talk about how the body handles it with the help of glucagon and insulin hormones.

  • Once Glucose is obtained from the consumed carbs in the digestive system after a meal, it's immediately absorbed and enters the bloodstream. Now this is a signal for the pancreas to start secreting Insulin, which is concerned with moderating the blood sugar levels.

  • When the insulin levels shoot up, the liver receives the signal of blood glucose being high, and thus, the glucose is absorbed by the liver. This absorbed glucose is later stored as a structure called Glycogen in the liver. Glycogen is the storage form of glucose in the body, from which glucose can be reproduced whenever necessary.

  • Insulin also acts on the muscle cells and heart cells, allowing them to use up the glucose available in the bloodstream after a meal as an energy source.

  • So Insulin basically grants access to glucose for the cells of the body, especially in the liver, muscles and heart to use them for their functioning. Once Insulin attaches to the insulin receptors on these cells, they open up and allow glucose to enter.

Other actions of Insulin Hormone

  • Other than its major role in maintaining blood sugar levels, Insulin also has other roles:

  • It helps in post-injury recovery as it promotes the spread of amino acids in muscles. Amino acids are building blocks of proteins which help in healing.

  • Insulin also enhances DNA and protein synthesis.

  • Insulin Hormone also plays an important role in the fat metabolism. Whenever the liver is saturated with glycogen form, insulin directs the surplus glucose in the blood towards fatty acid generation. Later these fatty acids are stored in the adipose tissue. This process of lipid generation is called lipogenesis. This fact can be correlated with the reason why many diabetic individuals on Insulin treatment gain weight.

What does Glucagon do?

  • The process by which glucose is handled by insulin during states of raised blood sugar level, the reversal of this process occurs whenever blood sugar levels are low, and this reversal is governed by Glucagon.

  • As we already saw, glucose is stored in glycogen form in the liver. When the blood sugar level drops down, glucagon helps in converting this stored glycogen back into glucose and raises its level in the bloodstream. This process occurs in states of low blood sugar like fasting states.

  • These two essential hormones are necessary for the proper functioning of the human body as haphazard changes in blood glucose levels can cause several complications.

Now that we have talked about the functions of insulin and glucagon, let's gain some insight regarding the diseases associated with Insulin hormone and Glucagon.

Diseases and Disorders associated with Hormones Insulin and Glucagon

Diseases and disorders associated with Hormones Insulin and Glucagon

There are plenty of diseases and disorders associated with the malfunctioning of hormones insulin and glucagon. In brief, some of the most important are :

1. Diabetes mellitus

  • Diabetes mellitus is the most common disease of the blood glucose based disease spectrum. Here blood sugar levels are high because of insulin deficiency. This deficit can either be because of non-production (type 1 diabetes) or because of resistance to the action of insulin by the cells of the body. The latter reason leads to type 2 diabetes mellitus which is the most common type of diabetes.

  • Apart from the above reasons, there are other causes which can lead to diabetes like: autoimmune causes, viral illnesses, metabolic causes, genetic disorders, gestational diabetes etc.

  • One thing to remember about Diabetes is that, even though insulin levels are defective here, the pancreas continues producing Glucagon. This can also make blood sugar levels shoot up.

  • Diabetes may be managed by just lifestyle modifications or may need oral anti diabetic drugs or Insulin injections.

2. Hypoglycemia

  • Hypoglycemia refers to the state when the blood sugar levels dip too low. The patient may experience symptoms like: confusion, dizziness, difficulty in speaking, nauseous, sweaty, shaky or unsteady, hungry.

  • This is an emergency and needs to be corrected immediately. As a first aid, the patient may eat a chocolate or drink a solution made by mixing two tablespoons of glucose powder or sugar in a glass of water.

  • Hypoglycemia occurs when insulin levels are too high or glucagon levels are too low. Hence, such patients can also receive a shot of Glucagon as an emergency measure to raise blood sugar levels.

3. Tumors

  • This is also widely possible. Malignant or benign tumors of the endocrine pancreatic system are possible.

  • These include insulinoma (tumor of the pancreas where insulin levels hit the roof leading to repeated hypoglycemic episodes), glucagonoma (tumor of the glucagon producing part of the pancreas, here the patient may develop excessive blood sugar levels). Such tumors may need surgical removal.

Take home pointers

  • So basically, Insulin and glucagon are vital for maintaining optimal ranges of blood sugar level.

  • Insulin allows the cells to take in glucose from the blood, while glucagon triggers a release of stored glucose from the liver.

FAQ on Insulin and Glucagon Hormone

1. Does the liver produce Glucagon?

Ans. Glucagon is produced by the pancreas.

2. Is glucagon a hormone?

Ans. Yes, glucagon is a hormone. Glucagon hormone is responsible for blood sugar level.

3. Is insulin a hormone?

Ans. Yes, insulin is a major hormone of the body, produced by pancreas which helps moderate blood sugar levels.

4. How does glucagon work?

Ans. Glucagon hormone has receptors at its main site of action - the liver. On acting on the liver, the stored glycogen there is converted back to glucose.

5. What cells release insulin?

Ans. Insulin hormone is produced by the Beta cells of the islets of Langerhans of the pancreas.


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