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Are Insulin And Glucagon Proteins

Anabolism, Catabolism, & Insulin: The Definitions I Go By

Anabolism, Catabolism, & Insulin: The Definitions I Go By

I just want to provide some basic definitions to illustrate the terms that I’m using & how I understand them, & to try to state my basic understandings as clearly as I know how to. Anabolism: The phase of metabolism in which simple substances are synthesized into the complex materials of living tissue. Catabolism: The metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy. Both of my sources for these definitions (through the clickable links) are worth looking at, because they include dictionary definitions from several sources, as well as Wikipedia articles which explain in more depth. Basically, anabolism means taking simpler stuff & using it to build more complex stuff within the body: amino acids into protein into muscle, blood glucose into adipose tissue (body fat), etc. Catabolism does the opposite: it breaks larger, more complex molecules into simpler stuff, usually with a release of energy, for example, burning off fat through exercise or going on a low-calorie starvation diet that leads to the loss of lean muscle mass. Insulin is anabolic in these ways: Insulin tranfers blood glucose to the liver & to muscle cells to either be burned for energy, or to be synthesized (that is, built into) glycogen. Glycogen is “animal carbohydrate” which can be burnt (catabolized) when quick energy is needed for exercise or an emergency. Insulin is anabolic because it helps build glycogen. [Edit: I misstated that. Actually, glycogen itself isn’t burnt for energy. Rather, it’s converted back into glucose (a conversion stimulated by the catabolic hormone glucagon) & the resulting glucose can then be burnt for energy.] Insulin transfers excess blood glucose, that is more than the body needs for its immediate energy requirements Continue reading >>

Effects Of Insulin And Glucagon On Carbohydrate And Protein (metabolism Of Adductor Muscle And Diaphragm

Effects Of Insulin And Glucagon On Carbohydrate And Protein (metabolism Of Adductor Muscle And Diaphragm

The addition of 1 milliunit of insulin/ml of medium increased the glucose uptake and lactate and pyruvate production of adductor fiber groups and diaphragms from control and pancreatectomized rats. Insulin increased the glycogen levels (2-hr incubation) in diaphragm but not in fiber groups. The slight effect of glucagon on glucose uptake and lactate production was probably due to a trace of insulin in the glucagon. Following pancreatectomy, the average percentage decrease in glucose uptake was 40% for fiber groups and 24% for diaphragm. With adductor muscle, lactate production rose and pyruvate production fell, following operation, while no changes were observed with diaphragm muscle. Glucagon, 20/xg/ml, increased amino N release by adductor fiber groups, but had no effect on the release by diaphragm muscle in the control series. These results may be interpreted as evidence that glucagon exerts an over-all catabolic effect on skeletal muscle protein, independent of the secretion of other hormones. Insulin had no effect on amino N release in fiber groups or diaphragm from control rats although, in concomitant experiments on carbohydrate metabolism, these preparations were sensitive to 1 milliunit/ml of insulin. In the diabetic series, insulin decreased amino N release by diaphragm but not by adductor muscle. The muscle fiber group having proved satisfactory for metabolic and hormonal investigation, further studies are in progress utilizing a similar preparation from the mulatto macaque monkey. Continue reading >>

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Glucagon, a pancreatic hormone produced by cells in the islets of Langerhans. Glucagon is a 29-amino-acid peptide that is produced specifically by the alpha cells of the islets. It has a high degree of similarity with several glucagon-like peptides that are secreted by cells scattered throughout the gastrointestinal tract. Glucagon secretion is stimulated by the ingestion of protein, by low blood glucose concentrations (hypoglycemia), and by exercise. It is inhibited by the ingestion of carbohydrates, an effect that may be mediated by the resultant increase in blood glucose concentrations and insulin secretion. Glucagon strongly opposes the action of insulin; it raises the concentration of glucose in the blood by promoting glycogenolysis, which is the breakdown of glycogen (the form in which glucose is stored in the liver), and by stimulating gluconeogenesis, which is the production of glucose from amino acids and glycerol in the liver. By increasing the concentration of glucose in the bloodstream, glucagon plays a critical role in maintaining blood glucose concentrations during fasting and exercise. Gastrointestinal glucagon, another form, is secreted into the blood when glucose is ingested; its only action appears to be to stimulate the secretion of insulin. Continue reading >>

Hormonal Control Of Glucose Levels

Hormonal Control Of Glucose Levels

The storage and metabolism of glucose is controlled at the organ level by hormones. The hormones glucagon and insulin are secreted by the pancreas during periods of low or high blood sugar, respectively. Glucagon causes the liver to produce glucose from the storage polysaccharide glycogen or to synthesize glucose from pyruvate using the pathway gluconeogenesis. The released glucose enters into the blood and travels to muscle for oxidation by glycolysis leading to energy production. In contrast, insulin instructs the liver cell to store the excess glucose in the blood. The hormone epinephrine,which is produced by the central nervous system in response to dangerous situations, evokes the same response as glucagon, the release of glucose from the liver. Hormonal control of glucose metabolism. Glucagon and insulin are pancreatic hormones that regulate blood sugar levels. Epinephrine (adrenaline) is produced by the adrenal gland in the central nervous system in response to dangerous situations. Glucagon and epinephrine instruct the liver cell to produce glucose by release from glycogen or by synthesis from pyruvate via the synthetic pathway gluconeogenesis. The glucose enters the blood and is oxidized in muscle cells to produce energy. Insulin is secreted when the blood glucose level is high, instructing the liver to store glucose in glycogen or, if necessary, to oxidize it to produce energy. These hormones do not directly affect the enzymes involved in glucose metabolism and storage. Rather they bind to membrane receptors on the surface of the cell and evoke a conformational, or allosteric, change in the receptor, transmitting the signal to the inside of the cell. The signalling pathway that is activated by the hormones glucagon and epinephrine begins with the activation of Continue reading >>

G-protein-coupled Receptors, Pancreatic Islets, And Diabetes

G-protein-coupled Receptors, Pancreatic Islets, And Diabetes

© 2010 Nature Education All rights reserved. Figure Detail Following a meal, glucose levels in the blood circulation increase. Multiple factors regulate the level of glucose in the blood, and central among these are insulin and glucagon. Glucose is taken up into pancreatic beta cells through a glucose transporter called GLUT2 (Figure 1). As glucose is taken up into beta cells, it is metabolized, which leads to an increased production of ATP. This, in turn, increases the ATP/ADP ratio, which results in closing of potassium channels in the cell membrane and subsequent depolarization of the cell. As potassium channels close and cell depolarization increases, this causes calcium channels in the cell membrane to open and allow the flow of calcium into the cell. This accumulation of calcium causes the secretion of insulin into the blood by particular cells in the islet called beta cells. Subsequently, insulin circulates and acts on cells in a variety of tissues. Important among these are fat, muscle, and liver. Insulin binds to a receptor for insulin in the plasma membrane of the cells in these tissues, and stimulates intracellular signaling pathways that ultimately cause the translocation of glucose transporters (GLUT4 in the case of fat and muscle cells) to the cell membrane. These transporters increase glucose uptake into the cell. In fat and muscle cells, glucose normally serves as an important source of energy which can be converted into fat or glycogen (as a form of stored energy) if necessary. In liver cells, an important function is to produce glucose (either by the breakdown of glycogen or de novo synthesis of glucose). The binding of insulin to its receptor on liver cells leads to increased synthesis of glycogen and inhibition of glucose production by liver cells. Continue reading >>

Are Hormones Considered To Be Protein?

Are Hormones Considered To Be Protein?

Sometimes but not always. There are three main classes of hormones: amino-acid based (amines/peptides/proteins), eicosanoids, and steroids. Peptide hormones and protein hormones (the former having a shorter amino acid chain) are synthesized from mRNA inside the cell nucleus just like any other protein or peptide. Prohormones are then typically processed in the endoplasmic reticulum to remove the N-terminus and the signal sequence. Sometimes glycosylation (addition of glycans) will be performed. These hormones can then be secreted by the cell in response to stimuli. Some common and well-known peptide/protein hormones include angiotensin, insulin, and glucagon. Continue reading >>

Protein Controversies In Diabetes

Protein Controversies In Diabetes

Diabetes SpectrumVolume 13 Number 3, 2000, Page 132 Marion J. Franz, MS, RD, LD, CDE In Brief People with diabetes are frequently given advice about protein that has no scientific basis. In addition, although weight is lost when individuals follow a low-carbohydrate, high-protein diet, there is no evidence that such diets are followed long-term or that there is less recidivism than with other low-calorie diets. People with type 1 or type 2 diabetes who are in poor metabolic control may have increased protein requirements. However, the usual amount of protein consumed by people with diabetes adequately compensates for the increased protein catabolism. People with diabetes need adequate and accurate information about protein on which to base their food decisions. In the United States, ~16% of the average adult consumption of calories is from protein, and this has varied little from 1909 to the present.1 Protein intake is also fairly consistent across all ages from infancy to older age. A daily intake of 2,500 calories contributes ~100 g of protein—about twice what is needed to replace protein lost on a daily basis. Excess amino acids must be converted into other storage products or oxidized as fuel. Therefore, in theory, the excess ingested protein could, through the process of gluconeogenesis, produce glucose. This would mean that 100 g of protein could produce ~50 g of glucose. This has been the basis of the statement that if about half of ingested protein is converted to glucose, protein will have one-half the effect of carbohydrate on blood glucose levels. However, this belief has been challenged.2-4 Protein controversies exist either because research has not provided conclusive answers or because professionals are not aware of the research. This article will review Continue reading >>

What Is Insulin?

What Is Insulin?

Insulin is a hormone; a chemical messenger produced in one part of the body to have an action on another. It is a protein responsible for regulating blood glucose levels as part of metabolism.1 The body manufactures insulin in the pancreas, and the hormone is secreted by its beta cells, primarily in response to glucose.1 The beta cells of the pancreas are perfectly designed "fuel sensors" stimulated by glucose.2 As glucose levels rise in the plasma of the blood, uptake and metabolism by the pancreas beta cells are enhanced, leading to insulin secretion.1 Insulin has two modes of action on the body - an excitatory one and an inhibitory one:3 Insulin stimulates glucose uptake and lipid synthesis It inhibits the breakdown of lipids, proteins and glycogen, and inhibits the glucose pathway (gluconeogenesis) and production of ketone bodies (ketogenesis). What is the pancreas? The pancreas is the organ responsible for controlling sugar levels. It is part of the digestive system and located in the abdomen, behind the stomach and next to the duodenum - the first part of the small intestine.4 The pancreas has two main functional components:4,5 Exocrine cells - cells that release digestive enzymes into the gut via the pancreatic duct The endocrine pancreas - islands of cells known as the islets of Langerhans within the "sea" of exocrine tissue; islets release hormones such as insulin and glucagon into the blood to control blood sugar levels. Islets are highly vascularized (supplied by blood vessels) and specialized to monitor nutrients in the blood.2 The alpha cells of the islets secrete glucagon while the beta cells - the most abundant of the islet cells - release insulin.5 The release of insulin in response to elevated glucose has two phases - a first around 5-10 minutes after g Continue reading >>

How Do I Lose Belly Fat In 1 Week?

How Do I Lose Belly Fat In 1 Week?

1 week is a tough task but you can lose some. It will have: zero to do with sit-ups, crunches, HIIT, cardio, walking, running or supplements. Zero to do with calorie deficit (disproven for decades) Fat loss is down to diet. I will answer your question but need to clear up a few misconceptions. ‘Calories in VS calories out’ does not work how people think it works. When it works, it is due to a happy coincidence and fat is hard to keep off for some. Not convinced? Please be open minded. Here’s why people lose or gain fat… Your body reacts differently to different foods regardless of calories. 100 calories from salad or 100 calories from a chocolate chip cookie. What will be more fattening? You already know which one is more fattening but knowing why one is more fattening is the key. Burning excess calories doesn’t work. Because the basic metabolic rate you supposedly have varies by upto 40% daily. So now you know that counting calories is not scientific but ‘sounds right’ So to lose belly fat you need to look at how the body stores and burns fat. How the body stores or burns fat. This process is controlled by two hormones (insulin and glucagon) that work like scales. Too much insulin and you’ll store fat, no insulin and glucagon can do it’s job and burn fat. The proof that hormones control fat storing and burning is common knowledge in the medical world and is not controversial. Yes there are hormones that control hunger and feeling full but in the end it’s all about being a fat burner or sugar burner. Don’t eat refined carbohydrates, sugars and fructose So avoid eating little and often, avoid refined carbohydrates, sugar and fructose. Don’t count calories. Just eat three or two times a day, high fat, moderate protein and low carb. Yes without a do Continue reading >>

Insulin And Glucagon: How To Manipulate Them And Lose Fat

Insulin And Glucagon: How To Manipulate Them And Lose Fat

I know many of you lean, mean, workout machine Breaking Muscle readers could care less about body fat reduction. You're already there. Your focus goes to your lift resistance amounts, improving training times, shoring up your exercise techniques, strategic planning to defeat your opponents, future competition preparation, and feeling good about your training. That's how it should be. What About Fat Loss? But guess what? There is a large segment of the population who are only concerned about shedding their "love handles.” Yes, most of these people will admit they're over-fat due to lack of physical activity and eating like it's Thanksgiving day multiple times per week. If taken to task, most people don't want to resemble an unshapely blob of protoplasm. They would rather look better, but they just don't know where to start to achieve that goal. On top of this, we all exist in a society where a plethora of high-calorie and/or low nutritional value food exists. Wise decisions must be made by all, regardless of your goals. Is it possible to eat your favorite foods, be happy, and attain your fitness goals simultaneously? Maybe. There are hundreds of diets and workout programs purportedly geared toward expunging body fat while enjoying your favorite foods. Many of them work, provided you actually adhere to their guidelines and remain disciplined with sensible calorie intake and exercise. But here’s my advice if you are attempting to maximally lose body fat: maintain your blood sugar level between 70 mg/dl and 110 mg/dl. Do this, and all other factors being equal, you will burn more fat. Biologically, it comes down to your body's innate ability to regulate two hormones - insulin and glucagon - relative to dietary intake. How Insulin and Glucagon Affect Fat Storage Insulin Continue reading >>

Protein, Amino Acids & Insulin & Glucagon Secretion In Humans

Protein, Amino Acids & Insulin & Glucagon Secretion In Humans

The purpose of this study is to determine the effect of various foods and/or food substances such as fats or proteins on the blood glucose and insulin concentrations in people with and without type 2 diabetes. Various foods or food substances are given as a test meal. The metabolic response is determined at various times after the administration of the meal (e.g. blood glucose, and other hormones and metabolites). Study Type : Interventional (Clinical Trial) Estimated Enrollment : 300 participants Allocation: Randomized Intervention Model: Crossover Assignment Masking: Single (Participant) Primary Purpose: Other Official Title: The Effect of Ingestion of Foods on the Plasma Glucose and Insulin Response in Subjects With Type 2 Diabetes: Protein, Amino Acids & Insulin & Glucagon Secretion in Humans Study Start Date : August 1982 Primary Completion Date : November 6, 2017 Estimated Study Completion Date : November 6, 2017 Resource links provided by the National Library of Medicine U.S. FDA Resources Arm Intervention/treatment Placebo Comparator: Control 240 ml water Other: water, glucose with or without amino acid 240 ml water, 50 g glucose ± 1 mmol amino acid/kg lean body mass Other Name: foods or food constituents Active Comparator: glucose 50 g glucose Other: water, glucose with or without amino acid 240 ml water, 50 g glucose ± 1 mmol amino acid/kg lean body mass Other Name: foods or food constituents Active Comparator: Amino acid 1 mmol amino acid/kg lean body mass Other: water, glucose with or without amino acid 240 ml water, 50 g glucose ± 1 mmol amino acid/kg lean body mass Other Name: foods or food constituents Active Comparator: amino acid plus glucose 50 g glucose plus 1 mmol amino acid/kg lean body mass Other: water, glucose with or without amino acid 240 ml Continue reading >>

Why Is The Pancreas Considered Endocrine And Exocrine?

Why Is The Pancreas Considered Endocrine And Exocrine?

The pancreas has two main functions: it is helping with digestion of food (that is the exocrine function). The enzymes produced are mainly lipase, trypsin and chymotrypsin. But the pancreas is also helping with stabilization of blood sugar by producing insulin and glucagon (this is the endocrine function of the pancreas). How Insulin and Glucagon Work. When you look closer, things are even more complicated: Glucagon is produced by the alpha cells (or A cells) in the islets of Langerhans. Insulin is produced in the more abundant beta cells (or B cells) in the islets of Langerhans. There is a third hormone produced in the islet of Langerhans: somatostatin. It is produced in the delta cells (or D cells). This hormone inhibits the production of insulin and glucagon, but also inhibits secretion of human growth hormone from the pituitary gland: Somatastatin. Finally, F cells in the islet of Langerhans produce pancreatic polypeptide (PP). Pancreatic polypeptide stimulates gastric juice secretion. PP is reduced in people after a full meal. But in patients with anorexia nervosa PP blood level are elevated. Continue reading >>

Glucagon

Glucagon

Glucagon has a major role in maintaining normal concentrations of glucose in blood, and is often described as having the opposite effect of insulin. That is, glucagon has the effect of increasing blood glucose levels. Glucagon is a linear peptide of 29 amino acids. Its primary sequence is almost perfectly conserved among vertebrates, and it is structurally related to the secretin family of peptide hormones. Glucagon is synthesized as proglucagon and proteolytically processed to yield glucagon within alpha cells of the pancreatic islets. Proglucagon is also expressed within the intestinal tract, where it is processed not into glucagon, but to a family of glucagon-like peptides (enteroglucagon). Physiologic Effects of Glucagon The major effect of glucagon is to stimulate an increase in blood concentration of glucose. As discussed previously, the brain in particular has an absolute dependence on glucose as a fuel, because neurons cannot utilize alternative energy sources like fatty acids to any significant extent. When blood levels of glucose begin to fall below the normal range, it is imperative to find and pump additional glucose into blood. Glucagon exerts control over two pivotal metabolic pathways within the liver, leading that organ to dispense glucose to the rest of the body: Glucagon stimulates breakdown of glycogen stored in the liver. When blood glucose levels are high, large amounts of glucose are taken up by the liver. Under the influence of insulin, much of this glucose is stored in the form of glycogen. Later, when blood glucose levels begin to fall, glucagon is secreted and acts on hepatocytes to activate the enzymes that depolymerize glycogen and release glucose. Glucagon activates hepatic gluconeogenesis. Gluconeogenesis is the pathway by which non-hexose Continue reading >>

What Can Happen If The Pancreas Stops Working?

What Can Happen If The Pancreas Stops Working?

Food consists of carbohydrates (e.g. starch), proteins (e.g. meat), and fat (e.g. butter), and digestion is not possible without the enzymes produced by the pancreas. All the body’s cells use glucose (sugar) as an energy source. The level of sugar in the blood is kept constant by insulin, which is made by special cells in the pancreas. If the cells are not working properly and insulin is lacking then diabetes develops. Depending upon how badly the pancreas fail there are two problems. The first is that food is poorly absorbed, which causes weight loss, and there is diarrhea, often rather fatty as the undigested fat causes pale, bulky and smelly motions. The second is, if too little insulin is made, diabetes develops with frequent passage of urine and weight loss. Failure of Pancreas may cause: Pseudocyst. Acute pancreatitis can cause fluid and debris to collect in cystlike pockets in your pancreas. A large pseudocyst that ruptures can cause complications such as internal bleeding and infection. Infection. Acute pancreatitis can make your pancreas vulnerable to bacteria and infection. Pancreatic infections are serious and require intensive treatment, such as surgery to remove the infected tissue. Kidney failure. Acute pancreatitis may cause kidney failure, which can be treated with dialysis if the kidney failure is severe and persistent. Breathing problems. Acute pancreatitis can cause chemical changes in your body that affect your lung function, causing the level of oxygen in your blood to fall to dangerously low levels. Diabetes. Damage to insulin-producing cells in your pancreas from chronic pancreatitis can lead to diabetes, a disease that affects the way your body uses blood sugar. Malnutrition. Both acute and chronic pancreatitis can cause your pancreas to produc Continue reading >>

Protein, Glucagon And Insulin

Protein, Glucagon And Insulin

Glucagon, Dietary Protein, and Low-Carbohydrate Diets The two basic hormones we need to keep in check are insulin and glucagon. Both are released by the pancreas in response to different foods. Eating carbohydrates raises blood sugar and stimulates the release of insulin. Insulin lowers the blood sugar by telling the body to store glucose for future use. The body creates glycogen, strings of glucose molecules, and stores it in the muscles and liver. Only the glycogen stored in the liver is available to return to circulation and keep adequate supplies of glucose going to the brain. The liver’s total capacity for storage is rather limited and is depleted within 10-12 hours. So the liver’s glycogen reserves must be continually replenished by eating carbohydrates. [Bee’s note: However 58% of protein and 10% of good fats also are made into glycogen by the body, so you do not need to replenish it by eating carbs.] The problem comes when excess carbohydrates are consumed. Once the liver and muscles have stored as much glycogen as possible (about the amount of three candy bars), the body creates another storage form, fat. Insulin tells your body not only to store new fat, but also not to release any previously stored fat. Insulin is the storage hormone. Glucagon [Note: this is different than Glycogen above], on the other hand, has the opposite effect to insulin. It tells the body to increase the blood sugar. It is the mobilization hormone. Protein stimulates the release of glucagon, which stimulates the liver to release stored carbohydrates from its glycogen stores and from fat. Glucagon also inhibits the release of insulin. By controlling your intake of protein and spreading it throughout the day, you can constantly produce adequate amounts of glucagon. Source: lowcarbdi Continue reading >>

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