Insulin

insulin genehuman insulinINSinsulin responseinsulin signalingblood insulindiscovery of insulinFasting InsulinhyperinsulinaemiaIletin
Insulin (from Latin insula, island) is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main anabolic hormone of the body.wikipedia
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Diabetes mellitus type 1

type 1 diabetesjuvenile diabetestype 1
This results in type 1 diabetes mellitus, which is characterized by abnormally high blood glucose concentrations, and generalized body wasting.
Diabetes mellitus type 1, also known as type 1 diabetes, is a form of diabetes mellitus in which very little or no insulin is produced by the pancreas.

Diabetes mellitus type 2

type 2 diabetestype II diabetestype 2 diabetes mellitus
In type 2 diabetes mellitus the destruction of beta cells is less pronounced than in type 1 diabetes, and is not due to an autoimmune process.
Diabetes mellitus type 2 (also known as type 2 diabetes) is a long-term metabolic disorder that is characterized by high blood sugar, insulin resistance, and relative lack of insulin.

Blood sugar regulation

glucose homeostasisblood glucose regulationblood sugar control
The secretion of insulin and glucagon into the blood in response to the blood glucose concentration is the primary mechanism of glucose homeostasis.
This tight regulation is referred to as glucose homeostasis. Insulin, which lowers blood sugar, and glucagon, which raises it, are the most well known of the hormones involved, but more recent discoveries of other glucoregulatory hormones have expanded the understanding of this process.

Glucagon

Their neighboring alpha cells, by taking their cues from the beta cells, secrete glucagon into the blood in the opposite manner: increased secretion when blood glucose is low, and decreased secretion when glucose concentrations are high.
Its effect is opposite to that of insulin, which lowers the extracellular glucose.

Dorothy Hodgkin

Dorothy Crowfoot HodgkinDorothy CrowfootDorothy
The crystal structure of insulin in the solid state was determined by Dorothy Hodgkin.
In 1969, after 35 years of work, Hodgkin was able to decipher the structure of insulin.

Glycogenesis

glycogen synthesisGlycogen biosynthesisglycogenetic
In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or [[Fatty acid metabolism#Glycolytic end products are used in the conversion of carbohydrates into fatty acids|fats]] (triglycerides) via lipogenesis, or, in the case of the liver, into both.
This process is activated during rest periods following the Cori cycle, in the liver, and also activated by insulin in response to high glucose levels, for example after a carbohydrate-containing sweet.

Fatty acid metabolism

biosynthesisfatty acid synthesisfatty acid catabolism
In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or [[Fatty acid metabolism#Glycolytic end products are used in the conversion of carbohydrates into fatty acids|fats]] (triglycerides) via lipogenesis, or, in the case of the liver, into both.
Lipolysis, the removal of the fatty acid chains from the glycerol to which they are bound in their storage form as triglycerides (or fats), is carried out by lipases. These lipases are activated by high epinephrine and glucagon levels in the blood (or norepinephrine secreted by sympathetic nerves in adipose tissue), caused by declining blood glucose levels after meals, which simultaneously lowers the insulin level in the blood.

Brockmann body

Insulin is produced by beta cells of the pancreatic islets in most vertebrates and by the Brockmann body in some teleost fish.
The islet tissues are in turn composed of endocrine cells which are the principal sites of insulin synthesis.

Frederick Sanger

Fred SangerSangerFred Sanger’s
The primary structure of bovine insulin was first determined by Frederick Sanger in 1951.
In 1958, he was awarded a Nobel Prize in Chemistry "for his work on the structure of proteins, especially that of insulin".

Pancreas

pancreaticexocrine pancreashead of the pancreas
Insulin is produced in the pancreas and the Brockmann body (in some fish), and released when any of several stimuli are detected.
As an endocrine gland, it secretes into the blood several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide.

Proinsulin

The C-peptide of proinsulin (discussed later), however, differs much more among species; it is also a hormone, but a secondary one.
Proinsulin is the prohormone precursor to insulin made in the beta cells of the islets of Langerhans, specialized regions of the pancreas.

Insulin resistance

insulin sensitivityresistantinsulin resistant
First-phase release and insulin sensitivity are independent predictors of diabetes.
Insulin resistance (IR) is considered as a pathological condition in which cells fail to respond normally to the hormone insulin.

C-peptide

C peptide
The endopeptidases cleave at 2 positions, releasing a fragment called the C-peptide, and leaving 2 peptide chains, the B- and A- chains, linked by 2 disulfide bonds.
The connecting peptide, or C-peptide, is a short 31-amino-acid polypeptide that connects insulin's A-chain to its B-chain in the proinsulin molecule.

Sulfonylurea

sulfonylureassulphonylureasulphonylureas
Other substances known to stimulate insulin release include the amino acids arginine and leucine, parasympathetic release of acetylcholine (acting via the phospholipase C pathway), sulfonylurea, cholecystokinin (CCK, also via phospholipase C), and the gastrointestinally derived incretins, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP).
They act by increasing insulin release from the beta cells in the pancreas.

Beta cell

beta cellsβ cellsβ-cell
Insulin is produced by beta cells of the pancreatic islets in most vertebrates and by the Brockmann body in some teleost fish. Insulin (from Latin insula, island) is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main anabolic hormone of the body.
Beta cells (β cells) are a type of cell found in pancreatic islets that synthesize and secrete insulin.

Secretion

secretedsecretesecretory pathway
Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood.
More modification can occur in the secretory vesicles (for example insulin is cleaved from proinsulin in the secretory vesicles).

Insulin receptor

INSRreceptor, insulinhuman insulin receptor–related
This is thought to avoid downregulation of insulin receptors in target cells, and to assist the liver in extracting insulin from the blood.
The insulin receptor (IR) is a transmembrane receptor that is activated by insulin, IGF-I, IGF-II and belongs to the large class of tyrosine kinase receptors.

Pulsatile insulin

delivering insulin rhythmicallyInsulin secretion
This may be achieved by delivering insulin rhythmically to the portal vein or by islet cell transplantation to the liver.
Pulsatile intravenous insulin therapy, sometimes called metabolic activation therapy, or cellular activation therapy describes in a literal sense the intravenous injection of insulin in pulses versus continuous infusions.

Post-translational modification

posttranslational modificationpost-translational modificationspost-translational
In the posttranslational modifications
For instance, the peptide hormone insulin is cut twice after disulfide bonds are formed, and a propeptide is removed from the middle of the chain; the resulting protein consists of two polypeptide chains connected by disulfide bonds.

Glucagon-like peptide-1

GLP-1glucagon-like peptide 1.
Other substances known to stimulate insulin release include the amino acids arginine and leucine, parasympathetic release of acetylcholine (acting via the phospholipase C pathway), sulfonylurea, cholecystokinin (CCK, also via phospholipase C), and the gastrointestinally derived incretins, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP).
Alongside glucose-dependent insulinotropic peptide (GIP), GLP-1 is an incretin; thus, it has the ability to decrease blood sugar levels in a glucose-dependent manner by enhancing the secretion of insulin.

OGT (gene)

OGTO-GlcNAc transferaseO-GlcNAc transferase (OGT)
It is localized in the cytosol, but in response to high glucose it becomes glycosylated by OGT and/or phosphorylated by ERK, which causes translocation to the nucleus.
OGT is involved in the resistance of insulin in muscle cells and adipocytes by inhibiting the Threonine 308 phosphorylation of AKT1, increasing the rate of IRS1 phosphorylation (at Serine 307 and Serine 632/635), reducing insulin signaling, and glycosylating components of insulin signals.

Islet cell transplantation

islet transplantationislet transplanttransplantation
This may be achieved by delivering insulin rhythmically to the portal vein or by islet cell transplantation to the liver.
Once transplanted, the islets begin to produce insulin, actively regulating the level of glucose in the blood.

Conserved sequence

sequence conservationconservedhighly conserved
Within vertebrates, the amino acid sequence of insulin is strongly conserved.
The discovery of the role of DNA in inheritance, and observations by Frederick Sanger of variation between animal insulins in 1949, prompted early molecular biologists to study taxonomy from a molecular perspective.

Potassium channel

potassium channelspotassiumpotassium ion channels
An increased intracellular ATP:ADP ratio closes the ATP-sensitive SUR1/Kir6.2 potassium channel (see sulfonylurea receptor). This prevents potassium ions (K + ) from leaving the cell by facilitated diffusion, leading to a buildup of intracellular potassium ions. As a result, the inside of the cell becomes less negative with respect to the outside, leading to the depolarization of the cell surface membrane.
They also regulate cellular processes such as the secretion of hormones (e.g., insulin release from beta-cells in the pancreas) so their malfunction can lead to diseases (such as diabetes).

Hypoglycemia

low blood sugarhypoglycemichypoglycaemia
Hypoglycemia, also known as "low blood sugar", is when blood sugar decreases to below normal levels.
The most common cause of hypoglycemia is medications used to treat diabetes mellitus such as insulin and sulfonylureas.