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Daily Insulin Secretion By Pancreas

Circadian Clock Controls Insulin And Blood Sugar In Pancreas

Circadian Clock Controls Insulin And Blood Sugar In Pancreas

Clock genes in pancreas produce proteins in rhythm with the planet’s daily rotation from light to dark Clocks operating in cells are fundamental to health When clocks are disrupted, metabolic disorders can develop CHICAGO --- A new Northwestern Medicine study has pinpointed thousands of genetic pathways an internal body clock takes to dictate how and when our pancreas must produce insulin and control blood sugar, findings that could eventually lead to new therapies for children and adults with diabetes. The body’s circadian clocks coordinate behaviors like eating and sleeping, as well as physiological activity like metabolism, with the Earth’s 24-hour light-dark cycle. There’s a master clock in the brain, as well as peripheral clocks located in individual organs. When genetics, environment or behavior disrupt the synchrony of these clocks, metabolic disorders can develop. In a previous publication in Nature, Northwestern Medicine investigators showed that a circadian clock in the pancreas is essential for regulating insulin secretion and balancing blood sugar levels in mice. The scientists demonstrated that knocking out clock genes led to obesity and type 2 diabetes, but they still had much to learn if they wanted to manipulate clock action to treat the conditions. “We knew that the pancreas didn’t work if we removed these clock genes, but we didn’t know how the genes were affecting the normal function of the pancreas,” said principal investigator Dr. Joe Bass, chief of endocrinology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician. Clock genes are responsible for producing transcription factors, special proteins that help tell a cell how to function. In the new study, published Nov. 6 in Science, Bass’s labo Continue reading >>

Is The End Of Insulin Jabs In Sight? New Treatment Made From Diabetics' Skin Could 'reboot' The Pancreas

Is The End Of Insulin Jabs In Sight? New Treatment Made From Diabetics' Skin Could 'reboot' The Pancreas

Hundreds of thousands of diabetics could be freed from insulin injections thanks to a treatment made from their own skin. Scientists have found a way of turning skin cells into healthy pancreatic cells, which could replace those damaged in type 1 diabetes. The breakthrough could spell the end to the grind of insulin injections. A more natural treatment should also cut the odds of developing the disabling and deadly complications of the disease, which range from heart attacks, strokes and blindness to nerve and circulatory damage and amputations. In diabetes, the body struggles to produce or use insulin, a hormone needed to convert the sugar in food into energy - so new treatments are urgently needed. The U.S. research capitalises on a technique that allows scientists to use a cocktail of vitamins, genes and other compounds to turn one type of cell into another. The researchers, from the Gladstone Institutes and the University of California, San Francisco, found the right recipe to turn human skin cells into healthy, fully-functional versions of the pancreatic beta cells that are damaged in diabetes. Grafted into a mouse, these cells worked well enough to stop the animals from developing the condition, the journal Nature Communications reports. Although insulin-producing cells have been made before, the new technique is quicker and more practical. In future, a sliver of skin could be taken from a patient’s arm and used to make trillions of healthy pancreatic beta cells. A perfect match to the patient, these customised cells could be put back into their body to replace those damaged by their diabetes. Researcher Dr Matthias Hebrok said: ‘Our results demonstrate for the first time that human adult skin cells can be used to efficiently and rapidly generate functional pa Continue reading >>

Amylin: The Other Hormone You Don’t Produce In Diabetes

Amylin: The Other Hormone You Don’t Produce In Diabetes

In type 1 diabetes and type 2 diabetes, we’re constantly thinking and talking about insulin. However, in type 1 diabetes, just as we don’t produce any insulin, we also don’t produce any of a hormone called “amylin.” In type 2 diabetes, just as your body isn’t producing enough or properly making use of the insulin you do still produce, the same is true for your body’s production of the hormone amylin. What is Amylin? “At the base of the pancreas,” explains Gary Scheiner, CDE and author of Think Like a Pancreas, “is a cluster of cells called the ‘islets of Langerhans,’ and contained within those cells are the cells that constantly measure blood glucose levels and produce insulin as needed to keep blood sugar within a normal range. Along with insulin, beta cells secrete amylin, a hormone that, among other things, regulates the rate at which food digests.” In type 1 diabetes, of course, those beta cells are attacked and destroyed by the immune system, therefore they produce zero insulin or amylin. In type 2 diabetes, your body doesn’t produce enough or doesn’t properly make use of the insulin and amylin produced by your beta cells. Amylin’s primary purpose in the human body is to prevent blood sugar levels from spiking too high after a meal. Amylin literally slows down the rate at which your stomach starts emptying digested food into the small intestine, where the glucose from the food you eat, as Scheiner explains, is then absorbed into the bloodstream. Amylin also decreases appetite after a meal, and, Scheiner explains, “blunts the secretion of glucagon by the pancreas” that is produced after a meal. (Yup, even in type 1 diabetics, our pancreas produces glucagon after we eat! How totally unhelpful!) Do We Need It? You might be wondering Continue reading >>

Pancreas: Function, Location & Diseases

Pancreas: Function, Location & Diseases

MORE The pancreas is an abdominal organ that is located behind the stomach and is surrounded by other organs, including the spleen, liver and small intestine. The pancreas is about 6 inches (15.24 centimeters) long, oblong and flat. The pancreas plays an important role in digestion and in regulating blood sugar. Three diseases associated with the pancreas are pancreatitis, pancreatic cancer and diabetes. Function of the pancreas The pancreas serves two primary functions, according to Jordan Knowlton, an advanced registered nurse practitioner at the University of Florida Health Shands Hospital. It makes “enzymes to digest proteins, fats, and carbs in the intestines” and produces the hormones insulin and glucagon, he said. Dr. Richard Bowen of Colorado State University’s Department of Biomedical Sciences wrote in Hypertexts for Pathophysiology: Endocrine System, “A well-known effect of insulin is to decrease the concentration of glucose in blood.” This lowers blood sugar levels and allows the body’s cells to use glucose for energy. Insulin also allows glucose to enter muscle and other tissue, works with the liver to store glucose and synthesize fatty acids, and “stimulates the uptake of amino acids,” according to Bowen. Insulin is released after eating protein and especially after eating carbohydrates, which increase glucose levels in the blood. If the pancreas does not produce sufficient insulin, type 1 diabetes will develop. Unlike insulin, glucagon raises blood sugar levels. According to the Johns Hopkins University Sol Goldman Pancreatic Cancer Research Center, the combination of insulin and glucagon maintains the proper level of sugar in the blood. The pancreas’ second, exocrine function is to produce and release digestive fluids. After food enters Continue reading >>

A Brand New Type Of Insulin-producing Cell Has Been Discovered Hiding In The Pancreas

A Brand New Type Of Insulin-producing Cell Has Been Discovered Hiding In The Pancreas

Researchers have found a brand new type of insulin-producing cell hiding in plain sight within the pancreas, and they offer new hope for better understanding - and one day even treating - type 1 diabetes. Type 1 diabetes occurs when a person's own immune system kills off most of their insulin-producing beta cells. And seeing as insulin is the hormone that regulates our blood sugar, type 1 diabetics are left reliant on injecting themselves with insulin regularly. While the condition can usually be managed effectively, in order to properly treat it, researchers would need to find a way to regenerate a patient's beta cells and prevent them from being attacked in future - something we're getting better at, but ultimately has eluded scientists so far. The discovery of these previously unnoticed cells in the pancreas - which the team are calling 'virgin beta cells' - could offer a new route for regrowing healthy, mature beta cells - and also provides insight into the basic mechanisms behind the disease. "We've seen phenomenal advances in the management of diabetes, but we cannot cure it," said lead researcher Mark Huising from the University of California, Davis. "If you want to cure the disease, you have to understand how it works in the normal situation." To get a better insight into exactly what happens in type 1 diabetes, the researchers studied both mice and human tissue. Huising and his team were looking at regions inside the pancreas known as the islets of Langerhans, which in healthy humans and mice are the regions that contain the beta cells that detect blood sugar levels around the body and produce insulin in response. Researchers also know that the islets contain cells called alpha cells, which produce glucagon, a hormone that raises blood sugar. These alpha cells, Continue reading >>

Brief Communication Uncoupling Protein 2 Regulates Daily Rhythms Of Insulin Secretion Capacity In Min6 Cells And Isolated Islets From Male Mice

Brief Communication Uncoupling Protein 2 Regulates Daily Rhythms Of Insulin Secretion Capacity In Min6 Cells And Isolated Islets From Male Mice

Highlights • Ucp2 mRNA expression in MIN6 β cells and isolated islets is dynamic and rhythmic over 24 h. • Daily cycles of glucose-stimulated insulin secretion capacity are dependent on rhythmic Ucp2 expression and UCP2 activity. • Loss of rhythmic Ucp2 mRNA expression triggers glucose intolerance only in the light/inactive phase of the daily cycle. • UCP2 is part of an endogenous diurnal metabolic regulator that coordinates islet function with the daily cycle of fasting and feeding. Abstract Upregulation of uncoupling protein 2 (UCP2) is associated with impaired glucose-stimulated insulin secretion (GSIS), which is thought to be an important contributor to pathological β cell failure in obesity and type 2 diabetes (T2D); however, the physiological function of UCP2 in the β cell remains undefined. It has been suggested, but not yet tested, that UCP2 plays a physiological role in β cells by coordinating insulin secretion capacity with anticipated fluctuating nutrient supply, such that upregulation of UCP2 in the inactive/fasted state inhibits GSIS as a mechanism to prevent hypoglycemia. Therefore, we hypothesized that daily cycles of GSIS capacity are dependent on rhythmic and predictable patterns of Ucp2 gene expression such that low Ucp2 in the active/fed phase promotes maximal GSIS capacity, whereas elevated Ucp2 expression in the inactive/fasted phase supresses GSIS capacity. We further hypothesized that rhythmic Ucp2 expression is required for the maintenance of glucose tolerance over the 24 h cycle. We used synchronized MIN6 clonal β cells and isolated mouse islets from wild type (C57BL6) and mice with β cell knockout of Ucp2 (Ucp2-βKO; and respective Ins2-cre controls) to determine the endogenous expression pattern of Ucp2 over 24 h and its impact o Continue reading >>

Insulin Regimens

Insulin Regimens

The goal of insulin therapy is to achieve optimal blood glucose control. Healthy, non-diabetic individuals usually maintain a blood glucose profile of 60 – 100 mg/dl overnight and before meals, and <140 mg/dl after meals. Specific blood glucose levels for diabetics are controversial but health providers often recommend overnight and pre-meal blood glucose of <90-130 mg/dl and post-meal blood glucose of <180 mg/dl.• Normally the pancreas secretes insulin in response to blood glucose levels. Pancreatic beta cells continuously release a small amount of insulin into the blood stream. Additional insulin is released in response to a rise in blood glucose that occurs after eating. The continuous release of insulin is known as basal secretion. Insulin released in response to an increase in blood sugar is known as bolus secretion. An individual's basal insulin requirement can vary due to physical stress, hormonal changes, physical activity, and over all health. Effective insulin regimens are individualized to reflect the patient's health, goals, lifestyle and ability for self-management. Designing an effective insulin regimen involves working with the patient to select a regimen that provides adequate insulin coverage and flexibility in regard to calorie intake, mealtime, physical activity, work schedule, other medications, psychosocial and economic factors. The insulin requirements of diabetic patients reflect the underlying disease. Type 1 diabetes (T1D) is the result of the complete or near complete absence of endogenous insulin secretion. Treatment involves replacing endogenous insulin secretion. In other words, optimum insulin delivery must provide continuous basal release with additional preprandial boluses reflecting the size and type of meals consumed. Basal insulin Continue reading >>

Insulin Synthesis And Secretion

Insulin Synthesis And Secretion

Insulin is a small protein, with a molecular weight of about 6000 Daltons. It is composed of two chains held together by disulfide bonds. The figure to the right shows a molecular model of bovine insulin, with the A chain colored blue and the larger B chain green. You can get a better appreciation for the structure of insulin by manipulating such a model yourself. The amino acid sequence is highly conserved among vertebrates, and insulin from one mammal almost certainly is biologically active in another. Even today, many diabetic patients are treated with insulin extracted from pig pancreas. Biosynthesis of Insulin Insulin is synthesized in significant quantities only in beta cells in the pancreas. The insulin mRNA is translated as a single chain precursor called preproinsulin, and removal of its signal peptide during insertion into the endoplasmic reticulum generates proinsulin. Proinsulin consists of three domains: an amino-terminal B chain, a carboxy-terminal A chain and a connecting peptide in the middle known as the C peptide. Within the endoplasmic reticulum, proinsulin is exposed to several specific endopeptidases which excise the C peptide, thereby generating the mature form of insulin. Insulin and free C peptide are packaged in the Golgi into secretory granules which accumulate in the cytoplasm. When the beta cell is appropriately stimulated, insulin is secreted from the cell by exocytosis and diffuses into islet capillary blood. C peptide is also secreted into blood, but has no known biological activity. Control of Insulin Secretion Insulin is secreted in primarily in response to elevated blood concentrations of glucose. This makes sense because insulin is "in charge" of facilitating glucose entry into cells. Some neural stimuli (e.g. sight and taste of food) Continue reading >>

Insulin

Insulin

This article is about the insulin protein. For uses of insulin in treating diabetes, see insulin (medication). Not to be confused with Inulin. Insulin (from Latin insula, island) is a peptide hormone produced by beta cells of the pancreatic islets, and it is considered to be the main anabolic hormone of the body.[5] It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of, especially, glucose from the blood into fat, liver and skeletal muscle cells.[6] In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both.[6] Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood.[7] Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells. Low insulin levels in the blood have the opposite effect by promoting widespread catabolism, especially of reserve body fat. Beta cells are sensitive to glucose concentrations, also known as blood sugar levels. When the glucose level is high, the beta cells secrete insulin into the blood; when glucose levels are low, secretion of insulin is inhibited.[8] Their neighboring alpha cells, by taking their cues from the beta cells,[8] secrete glucagon into the blood in the opposite manner: increased secretion when blood glucose is low, and decreased secretion when glucose concentrations are high.[6][8] Glucagon, through stimulating the liver to release glucose by glycogenolysis and gluconeogenesis, has the opposite effect of insulin.[6][8] The secretion of insulin and glucagon into the Continue reading >>

Pancreatic Cells Made To Produce Insulin Using Fda-approved Drug

Pancreatic Cells Made To Produce Insulin Using Fda-approved Drug

In a remarkable feat, scientists have managed to convert pancreatic tissue into insulin-producing cells, all without the need for genetic modification. And that’s not even the best part: The researchers achieved this outcome, a first for science, using a drug that’s already FDA-approved for use. This raises the possibility that one day, patients with type 1 diabetes might be able to ditch the daily jabs and start producing their own insulin again. The study has been published in Diabetes. In patients with type 1 diabetes, the immune system mistakenly sees insulin-producing cells of the pancreas, called beta-cells, as a foreign threat and destroys them. Patients must therefore regularly take insulin injections in order to control blood sugar, but even with proper management there is a risk of glucose levels entering the dangerous extremes. While much research has focused on improving insulin-delivery or monitoring systems, others are exploring the possibility of replacing this lost pancreatic tissue as a form of treatment. Transplants of insulin-producing cells have actually shown success, but with a shortage of donor tissue worldwide this isn’t a viable option for the masses. Another option scientists are looking into involves giving cells of the pancreas an identity swap. Most of the cells in this organ are actually not specialized for insulin production, and scientists have shown it’s possible to change their gene expression patterns so that they assume the identity of beta-cells. The problem with this approach is that studies involved genetic manipulation of cells, sometimes using viruses, which carries with it risks to the patient. But there could be an alternative. Researchers behind the present study previously discovered that the pancreas harbors a pool o Continue reading >>

Body Can Regain The Ability To Produce Insulin

Body Can Regain The Ability To Produce Insulin

Type 1 diabetes is a serious disease that affects many children and adolescents. The disease causes the pancreas to stop producing insulin, a hormone that regulates blood sugar levels. When blood sugar levels are too high, the smallest blood vessels in the body eventually become damaged. This can lead to serious health problems further down the line, including heart attacks, stroke, blindness, kidney failure and foot amputations. Professor Knut Dahl-Jørgensen and doctoral student Lars Krogvold are leading a research project, (DiViD), in which they want to ascertain among other things whether a virus in the pancreas might cause type 1 diabetes. They have previously discovered viruses in hormone-producing cells, the so-called islets of Langerhans, in the pancreas. Now their research has generated some new and surprising results. Recover the ability to produce insulin Lars Krogvold explains: “We found that the insulin-producing cells still have the ability to produce insulin when they are stimulated in the lab. But what’s new is our additional discovery that the cells increased their ability to produce insulin after a few days outside the body. Indeed, some became roughly as good at making insulin as cells from people without diabetes," he says. Some of the hormone-producing cells in the pancreas, the beta cells, produce insulin when they are stimulated by sugar. "Previous work has shown that you do not immediately lose your ability to produce insulin when you are first diagnosed with type 1 diabetes,” he says. Can improve patients’ daily lives “Our findings might mean that insulin production can be partially restored if we can find a way of stopping the disease process. The potential for insulin production is greater than previously thought," says Krogvold. "Th Continue reading >>

Understanding Our Bodies: Insulin

Understanding Our Bodies: Insulin

Almost everyone has heard of Insulin. You probably know that people with type 1 diabetes need to inject themselves with insulin to survive, and must constantly monitor the amount of sugar they eat. But what do you really know about insulin? What is its purpose in the body, and why do we need it? How does it relate to our diets? What happens when things go wrong with it? And why should anyone who doesn’t have diabetes give a hoot? Insulin is one of the most important hormones in the human body, and yet most people don’t really understand why our bodies make it or how what we eat affects the levels of insulin we produce. More so than any other hormone, our diet is key in regulating insulin levels, and thus a number of biological processes. As you’ll soon see, everyone should think about how what they eat impacts their body’s insulin release to be at their happiest and healthiest. Why We Need Insulin Every living thing requires energy to survive. In cells, energy is stored and shuttled around using a molecule called Adenosine Tri-Phosphate, or ATP. Whenever the cell then has an energy-requiring reaction, enzymes can use the energy stored in ATP’s phosphate bonds to fuel it. Cells rely on ATP to survive, and to create ATP, they rely on glucose. All cells, from bacteria and fungi to us, take glucose and use it to generate ATP by a process called Oxidative Phosphorylation. First, glucose is converted to an intermediate molecule called pyruvate via a process called glycolosis. As long as there is oxygen around, this pyruvate is further converted to Acetyl CoA, which enters a cycle of reactions called the Citric Acid Cycle. This takes the carbon to carbon bonds and uses them to create high energy electrons, which are then passed down a chain of enzymes which use the e Continue reading >>

Drugs To Increase Insulin Production

Drugs To Increase Insulin Production

Diabetes is a group of diseases that cause high blood sugar (glucose) levels. The high blood glucose levels are caused by problems in insulin production or function. Insulin is a hormone released by the pancreas when you eat food. It allows sugar to move from the blood into the cells, where it’s used for energy. If the cells of the body aren’t using insulin well, or if the body is unable to make enough insulin, glucose can build up in the blood. The increase in blood glucose levels may lead to uncomfortable symptoms, such as: constant thirst increased urination excessive hunger unintentional or unexplained weight loss fatigue or lack of energy irritability blurry vision wounds that heal more slowly than normal recurring or frequent infections There are two main types of diabetes. Type 1 diabetes develops when the body doesn’t make any insulin. It’s most often diagnosed during childhood, but it may be diagnosed later in life. Type 2 diabetes occurs when the body doesn’t produce enough insulin or doesn’t use insulin properly. It’s more commonly seen in adults, but the number of children with type 2 diabetes is increasing. Both types of diabetes cause a buildup of glucose in the bloodstream. This can lead to serious health problems, including: vision loss kidney damage skin problems hearing impairment heart disease stroke blood circulation problems limb amputation Most of these complications are preventable with treatment. Treatment plans for diabetes often involve monitoring blood glucose levels, following a healthy diet, and taking medications. Many of these medications work by raising the body’s insulin levels. Increased insulin production helps deliver the glucose in your blood to your cells. This prevents glucose from building up in your bloodstream. N Continue reading >>

Insulin Secretion And Sensitivity

Insulin Secretion And Sensitivity

Introduction In the 1930s Sir Harold Himsworth devised a primitive test of glucose disposal in response to insulin injection, and made the key observation that lean young people with or without diabetes respond similarly, whereas older overweight people with diabetes require much more insulin to achieve the same effect. From this he inferred that there were two types of diabetes: an insulin-sensitive form due to simple insulin deficiency, and an insulin-insensitive form in which the tissues were resistant to the actions of insulin.[1] In recent decades, observations in high-risk relatives have shown that clinical onset of type 1 diabetes is preceded by progressive glucose intolerance, loss of the FPIR, and loss of pulsatile insulin secretion. Progression to diabetes is more rapid in those who are less sensitive to insulin. Insulin secretion There are sub-populations of beta cells within healthy islets, and these have varying levels of responsiveness to glucose. Those with a low threshold for response are more active at normal glucose levels; others cut in at higher glucose levels.[2] Fully functional beta cells are metabolically very active, shedding and replacing 30–50% of their surface membrane daily in the course of insulin secretion. A lean healthy individual might secrete about 35 units of insulin per day, yet will have about 10 times this amount stored within his pancreas. By contrast, an obese insulin-resistant person might need to produce >100 units daily to maintain normal blood glucose levels. Type 1 diabetes results from progressive beta cell loss by apoptosis, thus increasing the work-load of the residue. A further consequence is loss of beta to beta cell communication and an altered cell-to-cell (paracrine) interaction between beta cells and glucagon-prod Continue reading >>

Pancreas And Insulin

Pancreas And Insulin

Your pancreas is one of the organs of your digestive system. It lies in your abdomen, behind your stomach. It is a long thin structure with 2 main functions: producing digestive enzymes to break down food; and producing the hormones insulin and glucagon to control sugar levels in your body. Production of digestive enzymes The pancreas produces secretions necessary for you to digest food. The enzymes in these secretions allow your body to digest protein, fat and starch from your food. The enzymes are produced in the acinar cells which make up most of the pancreas. From the acinar cells the enzymes flow down various channels into the pancreatic duct and then out into the duodenum. The secretions are alkaline to balance the acidic juices and partially digested food coming into the duodenum from the stomach. Production of hormones to control blood sugar levels A small proportion (1-2 per cent) of the pancreas is made up of other types of cells called islets of Langerhans. These cells sit in tiny groups, like small islands, scattered throughout the tissue of the pancreas. The islets of Langerhans contain alpha cells which secrete glucagon and beta cells which secrete insulin. Insulin and glucagon are hormones that work to regulate the level of sugar (glucose) in the body to keep it within a healthy range. Unlike the acinar cells, the islets of Langerhans do not have ducts and secrete insulin and glucagon directly into the bloodstream. Depending on what you’ve eaten, how much exercise your muscles are doing, and how active your body cells are, the amount of glucose in your bloodstream and cells varies. These 2 hormones have the job of keeping tight control of the amount of glucose in your blood so that it doesn’t rise or fall outside of healthy limits. How insulin works I Continue reading >>

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