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Names | |||
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Preferred IUPAC name 5,5-Dihydroxypyrimidine-2,4,6(1H,3H,5H)-trione | |||
Other names 5,5-Dihydroxybarbituric acid | |||
Identifiers | |||
3D model (JSmol) | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.000.057 | ||
EC Number |
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MeSH | Alloxan | ||
PubChem CID | |||
UNII |
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CompTox Dashboard (EPA) | |||
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Properties | |||
C4H4N2O5 | |||
Molar mass | 160.07 g/mol | ||
Appearance | pale yellow solid | ||
Density | 1.639 g/cm3 (anhydrous) | ||
Melting point | 254 °C (489 °F; 527 K) (decomposition) | ||
0.29 g/100 mL [2] | |||
Hazards | |||
Safety data sheet (SDS) | MSDS | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Alloxan, sometimes referred to as alloxan hydrate, is an organic compound with the formula OC(N(H)CO)2C(OH)2. It is classified as a derivative of pyrimidine. The anhydrous derivative OC(N(H)CO)2CO is also known, as well as a dimeric derivative. These are some of the earliest known organic compounds. They exhibit a variety of biological activities.
The compound was discovered by Justus von Liebig and Friedrich Wöhler. It is one of the oldest named organic compounds. It was originally prepared in 1818 by Luigi Valentino Brugnatelli (1761-1818) [3] [4] and was named in 1838 by Wöhler and Liebig. [5] The name "Alloxan" emerged from an amalgamation of the words "Allantoïn" and "Oxalsäure" (oxalic acid). The alloxan model of diabetes was first described in rabbits by Dunn, Sheehan and McLetchie in 1943. [6] The name is derived from allantoin, a product of uric acid excreted by the fetus into the allantois, and oxaluric acid derived from oxalic acid and urea, found in urine.
Alloxan was used in the production of the purple dye murexide, discovered by Carl Wilhelm Scheele in 1776. Murexide is the product of the complex in-situ multistep reaction of alloxantin and gaseous ammonia.[ citation needed ] Murexide results from the condensation of the unisolated intermediate uramil with alloxan, liberated during the course of the reaction.
Scheele sourced uric acid from human calculi (such as kidney stones) and called the compound lithic acid. William Prout investigated the compound in 1818 and he used boa constrictor excrement with up to 90% ammonium acid urate.
In the chapter "Nitrogen" of his memoir The Periodic Table, Primo Levi tells of his futile attempt to make alloxan for a cosmetics manufacturer who has read that it can cause permanent reddening of the lips. Levi considers the droppings of pythons as a source for uric acid for making alloxan, but he is turned down by the director of the Turin zoo because the zoo already has lucrative contracts with pharmaceutical companies, so he is obliged to use chickens as his source of uric acid. The synthesis fails, however, "and the alloxan and its resonant name remained a resonant name." [7]
It was originally obtained by oxidation of uric acid by nitric acid. It is prepared by oxidation of barbituric acid by chromium trioxide. [8]
A dimeric derivative alloxantin can be prepared by partial reduction of alloxan with hydrogen sulfide. [2]
Alloxan is a toxic glucose analogue, which selectively destroys insulin-producing cells in the pancreas (that is, beta cells) when administered to rodents and many other animal species. This causes an insulin-dependent diabetes mellitus (called "alloxan diabetes") in these animals, with characteristics similar to type 1 diabetes in humans. Alloxan is selectively toxic to insulin-producing pancreatic beta cells because it preferentially accumulates in beta cells through uptake via the GLUT2 glucose transporter. Alloxan, in the presence of intracellular thiols, generates reactive oxygen species (ROS) in a cyclic reaction with its reduction product, dialuric acid. The beta cell toxic action of alloxan is initiated by free radicals formed in this redox reaction. Studies suggests that alloxan does not cause diabetes in humans. [9] Others found a significant difference in alloxan plasma levels in children with and without diabetes Type 1. [10]
Because it selectively kills the insulin-producing beta-cells found in the pancreas, alloxan is used to induce diabetes in laboratory animals. [11] [12] This occurs most likely because of selective uptake of the compound due to its structural similarity to glucose as well as the beta-cell's highly efficient uptake mechanism (GLUT2). In addition, alloxan has a high affinity to SH-containing cellular compounds and, as a result, reduces glutathione content. Furthermore, alloxan inhibits glucokinase, a SH-containing protein essential for insulin secretion induced by glucose. [13]
Most studies have shown that alloxan is not toxic to the human beta-cell, even in very high doses, probably because of differing glucose uptake mechanisms in humans and rodents. [14] [15]
Alloxan is, however, toxic to the liver and the kidneys in high doses.
Insulin is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (INS) gene. It is the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood into cells of the liver, fat, and skeletal muscles. In these tissues the absorbed glucose is converted into either glycogen, via glycogenesis, or fats (triglycerides), via lipogenesis; in the liver, glucose is converted into both. Glucose production and secretion by the liver are strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is thus an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules in the cells. Low insulin in the blood has the opposite effect, promoting widespread catabolism, especially of reserve body fat.
The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e., it has both an endocrine and a digestive exocrine function. 99% of the pancreas is exocrine and 1% is endocrine. As an endocrine gland, it functions mostly to regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin and pancreatic polypeptide. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. This juice contains bicarbonate, which neutralizes acid entering the duodenum from the stomach; and digestive enzymes, which break down carbohydrates, proteins and fats in food entering the duodenum from the stomach.
Insulin resistance (IR) is a pathological condition in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia.
The following is a glossary of diabetes which explains terms connected with diabetes.
Beta cells (β-cells) are specialized endocrine cells located within the pancreatic islets of Langerhans responsible for the production and release of insulin and amylin. Constituting ~50–70% of cells in human islets, beta cells play a vital role in maintaining blood glucose levels. Problems with beta cells can lead to disorders such as diabetes.
Drugs used in diabetes treat diabetes mellitus by decreasing glucose levels in the blood. With the exception of insulin, most GLP-1 receptor agonists, and pramlintide, all diabetes medications are administered orally and are thus called oral hypoglycemic agents or oral antihyperglycemic agents. There are different classes of hypoglycemic drugs, and selection of the appropriate agent depends on the nature of diabetes, age, and situation of the person, as well as other patient factors.
Alpha cells (α-cells) are endocrine cells that are found in the Islets of Langerhans in the pancreas. Alpha cells secrete the peptide hormone glucagon in order to increase glucose levels in the blood stream.
An insulinoma is a tumour of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumour. Most insulinomas are benign in that they grow exclusively at their origin within the pancreas, but a minority metastasize. Insulinomas are one of the functional pancreatic neuroendocrine tumour (PNET) group. In the Medical Subject Headings classification, insulinoma is the only subtype of "islet cell adenoma".
Amylin, or islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. It is co-secreted with insulin from the pancreatic β-cells in the ratio of approximately 100:1 (insulin:amylin). Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels.
Pramlintide is an injectable amylin analogue drug for diabetes, developed by Amylin Pharmaceuticals. Pramlintide is sold as an acetate salt.
Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that occurs when pancreatic are destroyed by the body's immune system. Insulin is a hormone required by the body to store and convert blood sugar into energy. T1D results in high blood sugar levels in the body prior to treatment. Common symptoms include frequent urination, increased thirst, increased hunger, weight loss, and other complications. Additional symptoms may include blurry vision, tiredness, and slow wound healing. While some cases take longer, symptoms usually appear within weeks or a few months.
Streptozotocin or streptozocin (STZ) is a naturally occurring alkylating antineoplastic agent that is particularly toxic to the insulin-producing beta cells of the pancreas in mammals. It is used in medicine for treating certain cancers of the islets of Langerhans and used in medical research to produce an animal model for hyperglycemia and Alzheimer's in a large dose, as well as type 2 diabetes or type 1 diabetes with multiple low doses.
Glucose transporter type 4 (GLUT4), also known as solute carrier family 2, facilitated glucose transporter member 4, is a protein encoded, in humans, by the SLC2A4 gene. GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle. The first evidence for this distinct glucose transport protein was provided by David James in 1988. The gene that encodes GLUT4 was cloned and mapped in 1989.
Biguanide is the organic compound with the formula HN(C(NH)NH2)2. It is a colorless solid that dissolves in water to give a highly basic solution. These solutions slowly hydrolyse to ammonia and urea.
MODY 1 or HNF4A-MODY is a form of maturity onset diabetes of the young.
The insulin transduction pathway is a biochemical pathway by which insulin increases the uptake of glucose into fat and muscle cells and reduces the synthesis of glucose in the liver and hence is involved in maintaining glucose homeostasis. This pathway is also influenced by fed versus fasting states, stress levels, and a variety of other hormones.
Gliflozins are a class of drugs in the treatment of type 2 diabetes (T2D). They act by inhibiting sodium/glucose cotransporter 2 (SGLT-2), and are therefore also called SGLT-2 inhibitors. The efficacy of the drug is dependent on renal excretion and prevents glucose from going into blood circulation by promoting glucosuria. The mechanism of action is insulin independent.
Glybuzole is a hypoglycaemic medicine, mainly used to treat diabetes mellitus type 2. It is an oral antidiabetic drug (OAD), when administered in the right dose it will help bring the blood glycose level down by stimulating the insulin production. Similar medicines are glimepiride, glipizide, glibenclamide, gliclazide, and gliquidone.
Diabetes mellitus (DM) is a type of metabolic disease characterized by hyperglycemia. It is caused by either defected insulin secretion or damaged biological function, or both. The high-level blood glucose for a long time will lead to dysfunction of a variety of tissues.
Luigi Valentino Brugnatelli was an Italian chemist and inventor who discovered the process for electroplating in 1805.