Key Hormones - Glucagon
In an earlier blog on Key Hormones, we gave a summary of five hormones: insulin, glucagon, testosterone, oestrogen and human growth hormone (HGH). In another blog – Key hormones: Insulin – we focused on insulin, and how it helps to regulate blood sugar levels.
Glucagon, the subject of today’s blog, works in partnership with insulin as part of the Endocrine System to provide a steady supply of energy to the body.
Where does glucagon come from and why is it produced?
When our blood sugar levels fall, usually following exercise or if we haven’t eaten for a while, glucagon is secreted from alpha cells in the area of the pancreas known as the islets of Langerhans.
In effect, it provides fuel for us between each meal.
How does glucagon help regulate blood sugar levels?
It passes a message to the liver and muscle cells, which convert stored glycogen into glucose and releases it into the bloodstream in a process called glycogenolysis. The result is an increased concentration of glucose in the blood, balancing out the effect of low blood sugar levels.
It also causes gluconeogenesis – when amino acids are converted into glucose – and can break down tryglycerides (fats) stored in your cells into fuel for your body.
Very low blood sugar (hypoglycemia) is not only suffered by those with diabetes. It can be dangerous, as symptoms range from feeling dizzy and blurred vision to passing out. Glucagon works to avoid hypoglycemia.
How does glucagon relate to insulin?
Insulin is produced by the pancreas to help remove glucose from the blood when blood sugar levels rise after eating. Glucagon effectively achieves the opposite effect: introducing more glucose into the bloodstream when levels are low. The balance between these two hormones is vital in controlling our metabolism.
What happens if glucagon levels are too low?
This is rare and most likely to be seen in babies, although some people with very low blood sugar levels may be producing insufficient glucagon.
And too high?
Again, this is a rare occurrence, although it can sometimes be caused by a tumour in the pancreas and can cause diabetes or sudden weight loss.
How does this relate to our eating habits?
Generally, glucagon will be released around four to six hours after we eat a meal. The balance between glucagon and insulin is key for keeping our blood sugar levels stable and avoiding spikes, which can lead to the onset of Type 2 Diabetes. If you are not eating regularly enough and your blood sugar too drops too low, you will also probably be producing the 'hungry hormone' Grehlin. Therfore, if you go too long without eating this may lead to a voracious drive to eat resulting in cravings and poor dieatry choices.
Glucagon is one of the important hormones produced in the body, which the endocrine system needs for successful homeostasis – in other words, ensuring that our metabolism functions as it should (see our blog on: The Endocrine System).
Anyone who is concerned about their blood sugar levels or experiences symptoms common to diabetes should consult a medical professional.