Galactosamine

{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 461116190 | Reference = <ref>''Merck Index'', 11th Edition, '''4240'''.</ref> | ImageFile = galactosamine.png | ImageClass = skin-invert | ImageFile1 = D-(+)-Galactosamine Structural Formulae V.1.svg | ImageClass1 = skin-invert | ImageSize = | ImageSize1 = | IUPACName = 2-Amino-2-deoxy-D-galactose | OtherNames = α-D-galactosamine |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 22576 | ChEMBL_Ref = {{ebicite|changed|EBI}} | ChEMBL = 207280 | InChI = 1/C6H13NO5/c7-3-5(10)4(9)2(1-8)12-6(3)11/h2-6,8-11H,1,7H2/t2-,3-,4+,5-,6?/m1/s1 | InChIKey = MSWZFWKMSRAUBD-GASJEMHNBA | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C6H13NO5/c7-3-5(10)4(9)2(1-8)12-6(3)11/h2-6,8-11H,1,7H2/t2-,3-,4+,5-,6?/m1/s1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = MSWZFWKMSRAUBD-GASJEMHNSA-N | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 7535-00-4 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 4Y6R29688W | PubChem = 24154 | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 60312 | SMILES = O[C@H]1[C@@H](O)[C@H](OC(O)[C@@H]1N)CO }} |Section2={{Chembox Properties | C=6 | H=13 | N=1 | O=5 | Appearance = | Density = | MeltingPtC = 180 | MeltingPt_notes = (HCl salt) | BoilingPt = | Solubility = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}

'''Galactosamine''' is a hexosamine derived from galactose with the molecular formula C6H13NO5. This amino sugar is a constituent of some glycoprotein hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Precursors such as uridine diphosphate (UDP), UDP-''N''-acetyl-D-glucosamine, or glucosamine are used to synthesize galactosamine in the human body. A derivative of this compound is ''N''-acetyl-D-galactosamine.<ref name=":0"/>

Galactosamine is a hepatotoxic, or liver-damaging, agent that is sometimes used in animal models of liver failure.

== Hepatotoxicity == Galactosamine is used to induce hepatitis in rodent liver for research purposes. The result of using galactosamine to induce hepatitis is a disease model in which there is necrosis and inflammation of the liver. This type of tissue damage triggered by galactosamine resembles drug-induced liver disease in humans.<ref name=":1">{{Cite journal |last1=Das |first1=Joydeep |last2=Ghosh |first2=Jyotirmoy |last3=Roy |first3=Anandita |last4=Sil |first4=Parames C. |date=April 2012 |title=Mangiferin exerts hepatoprotective activity against D-galactosamine induced acute toxicity and oxidative/nitrosative stress via Nrf2–NFκB pathways |url=https://linkinghub.elsevier.com/retrieve/pii/S0041008X12000269 |journal=Toxicology and Applied Pharmacology |language=en |volume=260 |issue=1 |pages=35–47 |doi=10.1016/j.taap.2012.01.015|pmid=22310181 |url-access=subscription }}</ref>

=== Mechanism of hepatotoxicity === The proposed mechanism behind galactosamine-induced hepatitis is depletion of the energy source of hepatocytes. In the Leloir pathway galactosamine is metabolized into galactosamine-1-phosphate (by galactokinase) and UDP-galactosamine (by UDP-galactose uridyltransferase). It is hypothesized that this leads to UDP-galactosamine accumulation within cells, and uridine triphosphate (UTP), UDP, and uridine monophosphate (UMP) decrease.<ref name=":0">{{Citation |last=Apte |first=U. |title=Galactosamine |date=2014 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780123864543003158 |encyclopedia=Encyclopedia of Toxicology |pages=689–690 |publisher=Elsevier |language=en |doi=10.1016/b978-0-12-386454-3.00315-8 |isbn=978-0-12-386455-0 |access-date=2022-12-08|url-access=subscription }}</ref> The depletion of high-energy molecules such as UTP leads to a disruption in hepatocyte metabolism. Additionally, other derivatives of uridine such as UDP-glucose are depleted and this interferes with glycogen synthesis in the cell.

Another recent hypothesis states that overexpression of pro-inflammatory cytokines (such as tumor necrosis factor (TNFα) and NFκB-dependent inducible nitric oxide synthase (iNOS) over expression play a role in galactosamine-induced damage to liver cells.<ref name=":1" />

==See also== * ''N''-Acetylgalactosamine * Uridine

==References== {{More citations needed|date=March 2012}} {{Reflist}}

==External links== * {{MeshName|Galactosamine}}

Category:Hexosamines