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How does my body control my blood glucose level?

BMJ Group Medical Reference

Most people's bodies keep the amount of glucose (sugar) in their blood fairly constant. If the level gets too high or too low, you can become ill. For more, see What are the symptoms of type 1 diabetes?

And if your blood glucose level stays high over a long period of time, it can damage your heart, kidneys, eyes, feet, and other parts of your body. See What will happen to me? to find out about these extra problems.


Insulin and glucagon are two hormones that control how much glucose is in your blood. These hormones are made in your pancreas, a gland that sits just behind your stomach.

Your pancreas contains small groups of cells called the islets (or islands) of Langerhans. They are named after the German doctor who discovered them. These islets have two main types of cells:

  • Alpha cells make glucagon.

  • Beta cells make insulin.

What does insulin do?

When you eat, the amount of sugar in your blood rises. This causes the beta cells in your pancreas to make more insulin.

Almost all the cells in your body have special places on their surfaces that insulin sticks to. These are called insulin receptors. When insulin attaches to an insulin receptor, several things happen:

  • Glucose enters your cells (to give them energy).

  • Your liver stops making glucose, and starts storing it until your body needs more energy.

  • Cells in your muscles and in the fat under your skin pick up more glucose from your blood. This glucose is stored there until you need it.

All these things lower the level of glucose in your blood.

What does glucagon do?

Glucagon stops your blood glucose level dropping too low.

When you exercise, your muscles use the glucose in your blood for energy. Your pancreas senses that you're using up your glucose supply. As your blood glucose level drops:

  • Your pancreas stops making insulin

  • Your pancreas makes glucagon

  • Glucagon makes your liver, your muscles and the fat under your skin release some of the glucose stored there.

These activities increase the level of glucose in your blood.



A gland is any group of cells in the body that makes and releases something for use by another part of the body. For example, the thyroid gland makes a hormone called thyroxine. This acts on receptors within cells. By acting on the receptors it gives the cells a message to speed up their metabolism and work harder.


Hormones are chemicals that are made in certain parts of the body. They travel through the bloodstream and have an effect on other parts of the body. For example, the female sex hormone oestrogen is made in a woman's ovaries. Oestrogen has many different effects on a woman's body. It makes the breasts grow at puberty and helps control periods. It is also needed to get pregnant.


Your kidneys are organs that filter your blood to make urine. You have two kidneys, on either side of your body. They are underneath your ribcage, near your back.


Your liver is on the right side of your body, just below your ribcage. Your liver does several things in your body, including processing and storing nutrients from food, and breaking down chemicals, such as alcohol.

For more terms related to Diabetes, type 1


For references related to Diabetes, type 1 click here.
Last Updated: June 20, 2012
This information does not replace medical advice.  If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.

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