Guest Post by David Mapletoft, Diabetes Educator
Living with diabetes is hard work.
Understanding the changes in your blood glucose level can be frustrating and can lead to burnout. Here’s some information that is not often discussed when the subject of blood glucose level is raised with health care professionals.
There are other hormones other than insulin that affect the blood sugar levels in your body. To help you understand your blood glucose level it is important to know about glucagon, amylin, GIP, GLP-1, epinephrine, cortisol, and growth hormone.
The effects of glucagon are the opposite of the effects induced by insulin. The two hormones need to work in partnership with each other to keep blood glucose levels balanced.
Made by islet cells (alpha cells) in the pancreas, glucagon controls the production of glucose and another fuel, ketones, in the liver.
Glucagon is released overnight and between meals and is important in maintaining the body’s glucose and fuel balance. It signals the liver to break down its starch or glycogen stores and helps to form new glucose units and ketone units from other substances. It also promotes the breakdown of fat in fat cells.
In contrast, after a meal, when glucose from the ingested food rushes into your bloodstream, your liver doesn’t need to make glucose. The consequence? Glucagon levels fall.
In people living with diabetes the opposite occurs – while eating their glucagon levels rise, which causes the blood glucose level to rise after a meal.
More about glucagon here
GLP-1 & GIP
GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide) and amylin are other hormones that also regulate mealtime insulin. GLP-1 and GIP are incretin hormones. When released from your gut, they signal the beta cells to increase their insulin secretion and, at the same time, decrease the alpha cells’ release of glucagon. GLP-1 also slows down the rate at which food empties from your stomach, and it acts on the brain to make you feel full and satisfied.
People with type 1 diabetes have absent or malfunctioning beta cells so the hormones insulin and amylin are missing and the hormone GLP1 cannot work properly. This may explain, in part, why individuals with diabetes do not suppress glucagon during a meal and have high blood sugars after a meal.
GIP is made by cells in the upper small intestine and is released when glucose comes in contact with these cells. Like GLP-1, GIP affects the pancreatic beta cells, where it stimulates insulin secretion, and also appears to promote beta cell proliferation and beta cell survival.
More about GIP & GLP-1 here
Amylin is a peptide hormone that is cosecreted with insulin from the pancreatic β-cell and is thus deficient in diabetic people. It inhibits glucagon secretion, delays gastric emptying, and acts as a satiety agent.
Amylin is released along with insulin from beta cells. It has much the same effect as GLP-1. It decreases glucagon levels, which will then decrease the liver’s glucose production, slows the rate at which food empties from your stomach, and makes your brain feel that you have eaten a full and satisfying meal.
The overall effect of these hormones is to reduce the production of sugar by the liver during a meal to prevent it from getting too high
Epinephrine, cortisol, and growth hormone are other hormones that help maintain blood glucose levels. They, along with glucagon (see above) are called “stress” or “gluco-counter-regulatory” hormones – which means they make the blood glucose rise.
Epinephrine (adrenaline) is released from nerve endings and the adrenals, and acts directly on the liver to promote glucose production (via glycogenolysis). Epinephrine also promotes the breakdown and release of fat nutrients that travel to the liver where they are converted into glucose and ketones.
Cortisol is a steroid hormone also secreted from the adrenal gland. It makes fat and muscle cells resistant to the action of insulin, and enhances the production of glucose by the liver. Under normal circumstances, cortisol counterbalances the action of insulin. Under stress or if a synthetic cortisol is given as a medication (such as with prednisone therapy or cortisone injection), cortisol levels become elevated and you become insulin resistant. When you have Type 2 diabetes, this means your may need to take more medication or insulin to keep your blood glucose levels on target.
Growth hormone is released from the pituitary, which is a part of the brain. Like cortisol, growth hormone counterbalances the effect of insulin on muscle and fat cells. High levels of growth hormone cause resistance to the action of insulin.
So, the next time that you find an unusual blood glucose level – consider how complex our bodies are, and that there is much more than food that influences what that blood glucose level is like.
Diabetes self management is an art, and its ok to make mistakes. Its also important to realise that what you did may not be the cause of why your blood glucose level is above target. Working hand in hand with the ones you love, and your health care professional team, …..you can do it!
David Mapletoft, Diabetes Educator