Insulin where is it made

The islets of Langerhans are made up of different type of cells that make hormones, the commonest ones are the beta cells, which produce insulin. Insulin is then released from the pancreas into the bloodstream so that it can reach different parts of the body. Insulin has many effects but mainly it controls how the body uses carbohydrates found in certain types of food.

Carbohydrates are broken down by the human body to produce a type of sugar called glucose. Glucose is the main energy source used by cells. Insulin allows cells in the muscles, liver and fat adipose tissue to take up this glucose and use it as a source of energy so they can function properly. Without insulin, cells are unable to use glucose as fuel and they will start malfunctioning.

Extra glucose that is not used by the cells will be converted and stored as fat so it can be used to provide energy when glucose levels are too low. In addition, insulin has several other metabolic effects such as stopping the breakdown of protein and fat.

The main actions that insulin has are to allow glucose to enter cells to be used as energy and to maintain the amount of glucose found in the bloodstream within normal levels.

The release of insulin is tightly regulated in healthy people in order to balance food intake and the metabolic needs of the body. This is a complex process and other hormones found in the gut and pancreas also contribute to this blood glucose regulation. When we eat food, glucose is absorbed from our gut into the bloodstream, raising blood glucose levels. This rise in blood glucose causes insulin to be released from the pancreas so glucose can move inside the cells and be used.

As glucose moves inside the cells, the amount of glucose in the bloodstream returns to normal and insulin release slows down. Proteins in food and other hormones produced by the gut in response to food also stimulate insulin release. Hormones released in times of acute stress, such as adrenaline , stop the release of insulin, leading to higher blood glucose levels to help cope with the stressful event.

Insulin works in tandem with glucagon , another hormone produced by the pancreas. While insulin's role is to lower blood sugar levels if needed, glucagon's role is to raise blood sugar levels if they fall too low.

Using this system, the body ensures that the blood glucose levels remain within set limits, which allows the body to function properly. If a person accidentally injects more insulin than required, e.

This leads to abnormally low blood glucose levels called hypoglycaemia. The body reacts to hypoglycaemia by releasing stored glucose from the liver in an attempt to bring the levels back to normal.

Some of the symptoms that may occur include fatigue, constant infections, blurred eye sight, numbness, tingling in the hands or legs, increased thirst, and slowed healing of bruises or cuts. The cells will begin to use fat, the energy source stored for emergencies. When this happens for too long a time the body produces ketones, chemicals produced by the liver.

Ketones can poison and kill cells if they build up in the body over an extended period of time. This can lead to serious illness and coma. People who do not produce the necessary amount of insulin have diabetes. There are two general types of diabetes. The most severe type, known as Type I or juvenile-onset diabetes, is when the body does not produce any insulin.

Type I diabetics usually inject themselves with different types of insulin three to four times daily. Dosage is taken based on the person's blood glucose reading, taken from a glucose meter. Type II diabetics produce some insulin, but it is either not enough or their cells do not respond normally to insulin.

This usually occurs in obese or middle aged and older people. Type II diabetics do not necessarily need to take insulin, but they may inject insulin once or twice a day. There are four main types of insulin manufactured based upon how soon the insulin starts working, when it peaks, and how long it lasts in the body.

According to the American Diabetes Association, rapid-acting insulin reaches the blood within 15 minutes, peaks at minutes, and may last five hours. Short-acting insulin reaches the blood within 30 minutes, it peaks about two to four hours later and stays in the blood for four to eight hours.

Intermediate-acting insulin reaches the blood two to six hours after injection, peaks four to 14 hours later, and can last in the blood for hours. And long-acting insulin takes six to 14 hours to start working, it has a small peak soon after, and stays in the blood for hours.

Diabetics each have different responses to and needs for insulin so there is no one type that works best for everyone. Some insulin is sold with two of the types mixed together in one bottle. If the body does not produce any or enough insulin, people need to take a manufactured version of it. The major use of producing insulin is for diabetics who do not make enough or any insulin naturally.

Before researchers discovered how to produce insulin, people who suffered from Type I diabetes had no chance for a healthy life. Then in , Canadian scientists Frederick G. Banting and Charles H. Best successfully purified insulin from a dog's pancreas.

Over the years scientists made continual improvements in producing insulin. In , researchers found a way to make insulin with a slower release in the blood. They added a protein found in fish sperm, protamine, which the body breaks down slowly.

One injection lasted 36 hours. Another breakthrough came in when researchers produced a type of insulin that acted slightly faster and does not remain in the bloodstream as long. In the s, researchers began to try and produce an insulin that more mimicked how the body's natural insulin worked: releasing a small amount of insulin all day with surges occurring at mealtimes. Researchers continued to improve insulin but the basic production method remained the same for decades.

Insulin was extracted from the pancreas of cattle and pigs and purified. The chemical structure of insulin in these animals is only slightly different than human insulin, which is why it functions so well in the human body.

Although some people had negative immune system or allergic reactions. Then in the early s biotechnology revolutionized insulin synthesis. Researchers had already decoded the chemical structure of insulin in the mids.

They soon determined the exact location of the insulin gene at the top of chromosome By , a research team had spliced a rat insulin gene into a bacterium that then produced insulin.

Frederick Bonting. In , Frederick Banting was born in Alliston, Ontario. He graduated in from the University of Toronto medical school. In , Moses Barron, a researcher at the University of Minnesota, showed blockage of the duct connecting the two major parts of the pancreas caused shriveling of a second cell type, the acinar.

Banting believed that by tying off the pancreatic duct to destroy the acinar cells, he could preserve the hormone and extract it from islet cells. Macleod rejected Banting's proposal, but supplied laboratory space, 10 dogs, and a medical student, Charles Best.

Begining in May , Banting and Best tied off pancreatic ducts in dogs so the acinar cells would atrophy, then removed the pancreases to extract fluid from islet cells. Meanwhile, they removed pancreases from other dogs to cause diabetes, then injected the islet cell fluid. In January , 14 year-old Leonard Thompson became the first human to be successfully treat-ed for diabetes using insulin. Best received his medical degree in Banting insisted Best also be credited, and almost turned down his Nobel Prize because Best was not included.

Best became head of the University of Toronto's physiology department in and director of the university's Banting and Best Department of Medical Research after Banting's death in In the s, researchers used genetic engineering to manufacture a human insulin. In , the Eli Lilly Corporation produced a human insulin that became the first approved genetically engineered pharmaceutical product. Without needing to depend on animals, researchers could produce genetically engineered insulin in unlimited supplies.

It also did not contain any of the animal contaminants. Using human insulin also took away any concerns about transferring any potential animal diseases into the insulin. While companies still sell a small amount of insulin produced from animals—mostly porcine—from the s onwards, insulin users increasingly moved to a form of human insulin created through recombinant DNA technology.

Some companies have stopped producing animal insulin completely. Companies are focusing on synthesizing human insulin and insulin analogs, a modification of the insulin molecule in some way.

Human insulin is grown in the lab inside common bacteria. Escherichia coli is by far the most widely used type of bacterium, but yeast is also used. Researchers need the human protein that produces insulin. Manufacturers get this through an amino-acid sequencing machine that synthesizes the DNA. Manufacturers know the exact order of insulin's amino acids the nitrogen-based molecules that line up to make up proteins. There are 20 common amino acids. Manufacturers input insulin's amino acids, and the sequencing machine connects the amino acids together.

Also necessary to synthesize insulin are large tanks to grow the bacteria, and nutrients are needed for the bacteria to grow. Several instruments are necessary to separate and purify the DNA such as a centrifuge, along with various chromatography and x-ray crystallography instruments. Synthesizing human insulin is a multi-step biochemical process that depends on basic recombinant DNA techniques and an understanding of the insulin gene.

In January , Leonard Thompson, a year-old boy dying from diabetes in a Toronto hospital, became the first person to receive an injection of insulin. The news about insulin spread around the world like wildfire. Thank you, diabetes researchers! Soon after, the medical firm Eli Lilly started large-scale production of insulin. In the decades to follow, manufacturers developed a variety of slower-acting insulins, the first introduced by Novo Nordisk Pharmaceuticals, Inc. Eli Lilly went on in to sell the first commercially available biosynthetic human insulin under the brand name Humulin.

Insulin now comes in many forms, from regular human insulin identical to what the body produces on its own, to ultra-rapid and ultra-long acting insulins. Thanks to decades of research, people with diabetes can choose from a variety of formulas and ways to take their insulin based on their personal needs and lifestyles.

From Humalog to Novolog and insulin pens to pumps, insulin has come a long way.