Glucagon is a hormone produced in the body, managing blood sugar levels. Its function is to elevate glucose in the bloodstream. This action helps maintain the body’s energy balance, especially when blood sugar begins to drop. Glucagon works in opposition to insulin, which lowers blood sugar, ensuring glucose levels remain within a healthy range.
How Glucagon Regulates Blood Sugar
Glucagon is produced by alpha cells in the pancreas’s islets of Langerhans. When blood glucose levels decrease, these alpha cells release glucagon into the bloodstream. The main target organ for glucagon’s action is the liver.
Once it reaches the liver, glucagon initiates two processes to increase blood glucose. The first is glycogenolysis, where stored glycogen in the liver is broken down into glucose molecules. These glucose molecules are then released into the bloodstream, making energy available to the body’s cells.
The second mechanism is gluconeogenesis, which involves the synthesis of new glucose. This process uses non-carbohydrate sources, such as amino acids and fats, to create glucose in the liver. Glucagon also prevents the liver from taking in and storing glucose, ensuring more glucose remains in circulation.
These actions make glucagon a counter-regulatory hormone to insulin. While insulin helps cells absorb glucose from the blood, glucagon ensures that when blood sugar is low, the liver releases stored or newly created glucose. This regulatory partnership is important in preventing dangerously low blood sugar, known as hypoglycemia.
What Influences Glucagon’s Effect on Blood Sugar
The extent to which glucagon raises blood sugar can vary depending on several internal and external factors. The initial blood sugar level at the time glucagon is released or administered plays an important role. If blood glucose is already low, glucagon’s impact may be more pronounced as the body needs glucose.
The amount of glycogen stored in the liver influences glucagon’s effectiveness. Glucagon works by breaking down these stored glucose reserves. If liver glycogen stores are depleted, for instance, during prolonged fasting or in certain liver conditions, glucagon’s ability to raise blood sugar through glycogenolysis will be limited.
Individual differences in metabolism and hormone sensitivity contribute to variability in glucagon’s effect. Factors like a person’s overall health, the presence of other medical conditions like diabetes, and individual physiological responses to hormones can alter how effectively glucagon works. For example, in individuals with type 1 diabetes, the glucagon response to low blood sugar might be impaired.
The interplay with other hormones, particularly insulin, impacts glucagon’s action. High levels of insulin can blunt glucagon’s blood sugar-raising effect, as insulin promotes glucose uptake by cells and inhibits glucose release from the liver. Other hormones like cortisol and adrenaline can also influence blood sugar levels.
When glucagon is administered therapeutically, the dosage and route of administration affect its impact. Different forms, such as injectable solutions or nasal powders, can have varying rates of absorption and onset of action. A higher dose leads to a greater and faster increase in blood glucose.
When Glucagon is Used as a Treatment
Glucagon is an emergency treatment for severe hypoglycemia, where blood sugar levels drop dangerously low, often to the point where a person becomes unconscious or is unable to consume sugar by mouth. It is a rapid-acting solution to quickly restore blood glucose.
Therapeutic glucagon is available in various forms, including injectable kits that require mixing a powder with a liquid, pre-mixed injectable pens, and nasal powder devices. These formulations are designed for administration by a caregiver or family member, into the outer thigh, upper arm, or abdomen for injections, or into one nostril for the nasal spray.
After administration, blood sugar levels begin to rise within 10 to 15 minutes as the liver releases stored glucose. Once the person regains consciousness and can swallow, provide them with easily digestible carbohydrates, such as fruit juice or glucose tablets, followed by a longer-acting carbohydrate to prevent another drop in blood sugar.