Yes.
Although scientists know that glucose is the main factor in the release of glucagon, there are other factors including catecholamines (such as adrenaline) and amino acids (the “building blocks” of proteins) that also help stimulate glucagon release.
In addition, insulin and fatty acids can inhibit the release of glucagon.
There are many more factors, and scientists are currently trying to unravel the biology and hormone interactions in order to understand how cells respond (or don’t respond) when a person has diabetes.
How are the pancreas and insulin connected?
Insulin is made in the pancreas.
As the blood glucose levels rise after a person eats a meal, the pancreas is triggered to release insulin.
This hormone also enables the body’s cells to take in sugar and other nutrients.
It is necessary for energy and growth, which is why an imbalance of the hormone in the body (which most often means diabetes) can have a dramatic effect on a person’s entire body system.
When this system breaks down, in combination with other factors in the body, a person can develop insulin resistance, which is most often associated with type 2 diabetes. (For more about the pancreas, insulin resistance, and type 2 diabetes, see the chapter “Prediabetes and Type 2 Diabetes.”)
Who first described the pancreatic islets, and who discovered that the pancreas secreted insulin?
I n the late 1860s, German pathologist and biologist Paul Langerhans (1847, 1888) was the first to provide a detailed description of microscopic structures in the pancreas. What he found were uniquely shaped cells in the pancreas that were actually the islets. It was not until 1893 that French pathologist Gustave E. Laguesse (1861, 1927) discovered that these polygon-shaped cells were actually the endocrine cells of the pancreas that secreted insulin.
What is the function of insulin in the body?
Insulin is secreted when blood glucose levels rise above normal.
One of the most important tasks of insulin is to help with the transport of glucose across a cell’s membrane.
In other words, insulin allows the glucose in the blood to diffuse into most body cells.
It also stimulates the production of glycogen from glucose.
The glucose is then stored in the liver to be released when blood glucose levels drop, for example, when the body needs energy during exercise. (For more about insulin, see the chapter “Taking Charge of Diabetes.”)
Does insulin just control the body’s glucose levels?
No, insulin has other duties besides controlling the body’s glucose levels.
It also controls fat and helps the body store excess sugar as fat.
Certain sugars and other carbohydrates with a high glycemic index are most likely to be stored as fat in the body.
As the body’s sugar goes up and down before, during, and after meals, the insulin follows along, keeping the glucose levels even and contributing to the body’s fat stores. (For more about the glycemic index and how insulin and sugar are related to fat, see the chapter “Diabetes and Eating.”)
The Handy Diabetes Answer Book
HOW DIABETES AFFECTS THE NERVOUS SYSTEM
THE NERVOUS SYSTEM AND DIABETES
What is the human nervous system?
The human nervous system is an intricately organized, interconnected system of nerve cells that relays messages to and from the brain and spinal cord (nervous systems are also found in organisms called vertebrates, or, literally, organisms with backbones, a group that includes humans).
The human nervous system receives sensory input, processes the input, and then sends messages to the tissues and organs for the appropriate response.
In humans (and other vertebrates), there are two parts to the nervous system.
They are the central nervous system, consisting of the brain and spinal cord, and the peripheral system, consisting of peripheral nerves that carry signals to and from the central nervous system.
Do some diseases that affect the nervous system have connections to diabetes?
Although there are several diseases of the nervous system, the more well-known ones are epilepsy, multiple sclerosis (MS), and Parkinson’s disease.
The two with the most possible connections to diabetes are epilepsy and Parkinson’s disease (see below), but not multiple sclerosis. (MS is an autoimmune disease.
It is a chronic, potentially debilitating disease that affects the sheaths surrounding the nerves [called myelin] in the central nervous system.
In MS, the body directs antibodies and white blood cells against proteins in the sheaths, causing injury and inflammation to the sheaths, especially those surrounding nerves in the brain and spinal cord.) Overall, there is little evidence that diabetes, either type 1 or type 2, has any connection to MS, although people with either disease can develop the other one.
How are seizures connected to diabetes?
Seizures, or a condition in which something interrupts the normal connections between the nerve cells and the brain, can under some circumstances be connected to diabetes.
The definitions of seizures and shocks often differ depending on the research, but either way, a very low blood glucose reading can lead to a seizure.
In particular, a hypoglycemic seizure from low blood glucose levels can cause clumsiness, weakness, trouble talking, confusion, loss of consciousness, seizures, or (rarely) death.
Diabetic shock (severe hypoglycemia), also called insulin reaction, is a consequence of too much insulin.
It can occur anytime there is an imbalance between the insulin in the person’s system, the amount of food eaten, or the level of a person’s physical activity.
Hypoglycemic shock is similar (if not the same) as diabetic shock, caused by extremely low blood glucose levels, most often from an excessive amount of injected insulin, failure to eat after an insulin injection, or rarely by an insulin-secreting tumor of the pancreas.
Whatever it is called, an extremely low blood glucose level can cause seizures and is considered to be a medical emergency.
Is epilepsy connected to diabetes?
Epilepsy is a nervous system disorder in which clusters of nerve cells (neurons) in the brain sometimes send signals abnormally.
When the normal pattern of nerve activity becomes disturbed, it causes strange sensations, emotions, and behavior or sometimes convulsions, muscle spasms, and loss of consciousness.
There are thought to be many causes, including certain illnesses, brain damage, abnormal brain development and wiring, an imbalance of nerve-signaling chemicals (called neurotransmitters), or some combination of these factors.
As for epilepsy’s connection to diabetes, it is thought that there may be an increased risk, nearly three times more, of epileptic seizures in young people with type 1 diabetes as compared to others without type 1.
One study also suggests that there may be an association between epilepsy and diabetic ketoacidosis in children with type 1 diabetes. (For more about diabetic ketoacidosis, see the chapter “Type 1 Diabetes.”) As most researchers mention, more studies need to be conducted to determine whether there is a definite connection.
Is there a relationship between Parkinson’s disease and diabetes?
Several studies suggest a connection between Parkinson’s disease and diabetes, including one report indicating that people with type 2 diabetes were 80 percent more likely to be diagnosed with Parkinson’s disease.
Parkinson’s is a progressive neurological disorder (also called a neurodegenerative disease) that results from degeneration of neurons in a region of the brain that controls movement.
This degeneration creates a shortage of the brain-signaling chemical (neurotransmitter) known as dopamine, causing changes in body movement, most often shaking of various parts of the body, including hands and head, that characterize the disease.
No one knows whether there truly is a relationship, but one study suggests that many lifestyle factors, such as being overweight or obese, smoking, and being sedentary, seem to be associated with both disorders.
Parkinson’s disease is caused when an area of the brain called the substantia nigra deteriorates, which lowers dopamine production, an essential chemical for muscle control. Patients with diabetes are more likely to get Parkinson’s, but a direct connection has not yet been established.
What recent research addresses why there may be a link between Parkinson’s disease and type 2 diabetes?
In 2015, a study conducted at Ben Gurion University in Israel indicated that there may be a link between type 2 diabetes and Parkinson’s based on certain proteins.
The researchers were the first to discover the structure of a brain protein (alpha-synuclein) that can trigger Parkinson’s by clumping and causing the death of nerve cells.
There is also a protein (a short chain of amino acids) called amylin found in the pancreas in 95 percent of the people with type 2 diabetes, and it is also found in the brain. (In the pancreas, the amylin can harm insulin-producing beta cells, contributing to type 2 diabetes.) The researchers then studied a snippet of the brain protein alpha-synuclein (the snippet was called a non-amyloid-beta component, or NAC).
Because of their research, they believe that the NAC and amylin may act together, causing the clumping in the brain and killing nerve cells, a possible link between both diseases.
Researchers believe that if there is such a link, a drug may be developed that would prevent the interactions between the NAC component and the amylin.
But as with many new discoveries, more research needs to be conducted on the possible link between the two diseases.
DIABETES AND NEUROPATHY
What is neuropathy?
Neuropathy is the general term that means nerve damage caused by various conditions that affect the body.
It usually refers to the damage of a person’s peripheral nerves (see below), as opposed to the nerves of the central nervous system (the brain and spinal cord).
The nerves affected can be singular (mononeuropathy) or in sets (polyneuropathy).
For example, in polyneuropathy, multiple nerves simultaneously malfunction, causing weak hands and feet, as well as the loss of sensation in those areas.
What are the three types of nerves in the body that can be affected by neuropathy?
Overall, neuropathy for various reasons can occur if there is damage to three types of nerves (any number of these three types can affect a person at any one time):
Autonomic , The nerves that control the major systems of the body, such as the bladder; they can cause changes in a person’s heart rate and blood pressure, along with sweating.
Motor , The nerves that allow the body to have power and movement; neuropathy of motor nerves can cause weakness in the hands and feet.
Sensory , These nerves control sensation; neuropathy of sensory nerves can cause pain, tingling, numbness, or weakness in the hands and feet.
What are the common types of nerve damage often found in people with diabetes?
Not every person with diabetes will experience nerve damage, but for those who do, there are three different types of neuropathy:
Peripheral neuropathy , This is the most common type of neuropathy, and one of the major complications, in people with diabetes. It affects the long nerves that run from the spine to the arms, legs, and hands. Most researchers believe it is likely caused by damage to the delicate nerve fibers when the body experiences high blood glucose levels (see below). It is often called “diabetic peripheral neuropathy” (or “peripheral diabetic neuropathy”) if these nerves are damaged from diabetes.
Focal neuropathy , This type of nerve damage affects a specific nerve or set of nerves and usually causes weakness in the face, arms, legs, or eye muscles. It often leads to weakness in the hands, double vision, or difficulty in raising the legs. If treated (most often by controlling the person’s glucose levels), it typically disappears in two to six months.