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Glucagon Explained by Dr. Harshfield.


Glucagon is a hormone that your pancreas makes to help regulate your blood glucose (sugar) levels. Glucagon increases your blood sugar level and prevents it from dropping too low, whereas insulin, another hormone, decreases blood sugar levels.

What is glucagon? Glucagon is a natural hormone your body makes that works with other hormones and bodily functions to control glucose (sugar) levels in your blood. Glucagon prevents your blood sugar from dropping too low. The alpha cells in your pancreas make glucagon and release it in response to a drop in blood sugar, prolonged fasting, exercise and protein-rich meals.

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.

Your pancreas is a glandular organ in your abdomen that secretes several enzymes to aid in digestion and several hormones, including glucagon and insulin. It’s surrounded by your stomach, intestines and other organs.

Glucose is the main sugar found in your blood. You get glucose from carbohydrates in the food you eat. This sugar is an important source of energy and provides nutrients to your body's organs, muscles and nervous system. Glucose is very important because it’s the primary source of energy for your brain.

Your body normally has a complex system to make sure your blood sugar is at optimum levels. If you have too much or too little glucose in your blood, it can cause certain symptoms and complications.

Glucagon injections and nasal sprays

There’s also a synthetic form of glucagon that can be administered as an injection or nasal powder (dry nasal spray). People with Type 1 diabetes primarily use this form of glucagon in emergency situations when they have very low blood sugar. Synthetic glucagon triggers your liver to release stored glucose, which then raises blood sugar.

What is the function of glucagon?

Your body normally carefully regulates your blood glucose (sugar) primarily with the hormones glucagon and insulin. When your blood glucose levels trend lower or fall too low (hypoglycemia), your pancreas releases more glucagon. Glucagon helps blood glucose levels rise back up in multiple ways, including:

Glucagon triggers your liver to convert stored glucose (glycogen) into a usable form and then release it into your bloodstream. This process is called glycogenolysis.

Glucagon can also prevent your liver from taking in and storing glucose so that more glucose stays in your blood.

Glucagon helps your body make glucose from other sources, such as amino acids.

If your blood glucose levels trend higher, your pancreas releases insulin to bring it back into range.

What is the difference between glucagon and insulin?

Glucagon and insulin are both important hormones that play essential roles in regulating your blood glucose (sugar). Both hormones come from your pancreas — alpha cells in your pancreas make and release glucagon, and beta cells in your pancreas make and release insulin.

The difference is in how these hormones contribute to blood sugar regulation. Glucagon increases blood sugar levels, whereas insulin decreases blood sugar levels. If your pancreas doesn’t make enough insulin or your body doesn’t use it properly, you can have high blood sugar (hyperglycemia), which leads to diabetes.

What is the difference between glucagon and glycogen?

Glucagon and glycogen are not the same. Glycogen is a stored form of glucose (sugar). Your body primarily stores glycogen in your liver and muscles.

Glucagon is a hormone that triggers liver glycogen to convert back into glucose and to enter your bloodstream so that your body can use it for energy.

What tests can check glucagon levels?

Healthcare providers don’t typically order glucagon level tests for people with diabetes, but they may order the test to help diagnose some rare endocrine conditions.

Your provider may order a glucagon blood test to measure your glucagon levels if you’re having certain symptoms. During the test, a provider will draw a blood sample from your vein using a needle. They will then send it to a lab for testing.

What are normal glucagon levels?

Normal glucagon value ranges can vary from lab to lab and depending on the duration of fasting and blood glucose level(s).

In general, the normal range of glucagon levels in your blood is 50 to 100 picograms per milliliter (pg/mL). A picogram is one-trillionth of a gram.


C-peptide is a useful and widely used method of assessing pancreatic beta cell function. After cleavage of proinsulin, insulin and the 31-amino-acid peptide c-peptide are produced in equal amounts. So why is c-peptide testing preferable to insulin as a guide to beta cell function? The degradation rate of c-peptide in the body is slower than that of insulin (half-life of 20–30 min, compared with the half-life of insulin of just 3–5 min), which affords a more stable test window of fluctuating beta cell response.

In healthy individuals the plasma concentration of c-peptide in the fasting state is 0.3–0.6 nmol/l, with a postprandial increase to 1–3 nmol/l. Half of all insulin secreted by the pancreas is metabolized in the liver by first-pass metabolism, whereas c-peptide has negligible hepatic clearance. C-peptide is cleared in the peripheral circulation at a constant rate, whereas insulin is cleared variably making direct measurement less consistent. In insulin-treated patients with diabetes, measurement of c-peptide also avoids the pitfall of cross-reaction of assay between exogenous and endogenous insulin.

C-peptide is a cornerstone of the assessment of non-diabetes-associated hypoglycemia and the diagnosis of conditions such as insulinoma and factitious hypoglycemia but this area is beyond the scope of this article.

Increasing evidence suggests that c-peptide may also be useful in predicting future levels of glycemic control, response to hypoglycemic agents, and risk of future diabetes complications. We will examine the key methods of sample collection for c-peptide determination and advise on what is most reliable and practical. Furthermore, we will summarize the clinical relevancy of c-peptide sampling through review of the evolving literature on this subject.


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