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.

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.

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.

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.

Anabolism

anabolicanabolic effectsanabolic pathway
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.
The classic anabolic hormones are the anabolic steroids, which stimulate protein synthesis and muscle growth, and 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).

Liver

hepaticliver protein synthesislivers
It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of carbohydrates, especially glucose from the blood into liver, fat and skeletal muscle cells.
The liver is responsible for the breakdown of insulin and other hormones.

Glycogen

glycogen depositsglycogen (n)glycogen deposits
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.
As a meal containing carbohydrates or protein is eaten and digested, blood glucose levels rise, and the pancreas secretes insulin.

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".

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.

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.

Lipogenesis

conversion of carbohydratesde novo'' lipogenesisLIPA gene
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.
Insulin is a peptide hormone that is critical for managing the body's metabolism.

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.

Glucose

dextrose D -glucoseglucopyranose
Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of carbohydrates, especially glucose from the blood into liver, fat and skeletal muscle cells. 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.
The glucose content of the blood is regulated by the hormones insulin, incretin and glucagon.

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.

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.

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.

Obesity

obesemorbidly obeseoverweight
Low insulin levels in the blood have the opposite effect by promoting widespread catabolism, especially of reserve body fat.
Certain medications may cause weight gain or changes in body composition; these include insulin, sulfonylureas, thiazolidinediones, atypical antipsychotics, antidepressants, steroids, certain anticonvulsants (phenytoin and valproate), pizotifen, and some forms of hormonal contraception.

NEUROD1

neurogenic differentiation 1Beta2/NeuroD1NeuroD1 (NeuroD)
Insulin is mainly regulated through the transcription factors PDX1, NeuroD1, and MafA.
It regulates expression of the insulin gene, and mutations in this gene result in type II diabetes mellitus.

PDX1

insulin promoter factor-1
Insulin is mainly regulated through the transcription factors PDX1, NeuroD1, and MafA.
Pdx1 is also necessary for β-cell maturation: developing β-cells co-express Pdx1, NKX6-1, and insulin, a process that results in the silencing of MafB and the expression of MafA, a necessary switch in maturation of β-cells.