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|Section2= |Section6= }} Chenodeoxycholic acid (also known as chenodesoxycholic acid, chenocholic acid and 3α,7α-dihydroxy-5β-cholan-24-oic acid) is a bile acid. It occurs as a white crystalline substance insoluble in water but soluble in alcohol and acetic acid, with melting point at 165-167 °C. Salts of this carboxylic acid are called chenodeoxycholates. Chenodeoxycholic acid is one of the main bile acids produced by the liver. It was first isolated from the bile of the domestic goose, which gives it the "cheno" portion of its name (Greek: χήν = goose). Chenodeoxycholic acid and cholic acid are the two primary bile acids in humans. Some other mammals have muricholic acid or deoxycholic acid rather than chenodeoxycholic acid.〔 Chenodeoxycholic acid is synthesized in the liver from cholesterol by a process which involves several enzymatic steps.〔 Like other bile acids, it can be conjugated in the liver with taurine or glycine, forming taurochenodeoxycholate or glycochenodeoxycholate. Conjugation results in a lower pKa. This means the conjugated bile acids are ionized at the usual pH in the intestine and will stay in the gastrointestinal tract until reaching the ileum where most will be reabsorbed. Bile acids form micelles which facilitate lipid digestion. After absorption, they are taken up by the liver and resecreted, so undergoing an enterohepatic circulation. Unabsorbed chenodeoxycholic acid can be metabolised by bacteria in the colon to form the secondary bile acid known as lithocholic acid. Choendeoxycholic acid is the most potent natural bile acid at stimulating the nuclear bile acid receptor, farnesoid X receptor (FXR). The transcription of many genes is activated by FXR. ==Therapeutic applications== Chenodeoxycholic acid has been used as medical therapy to dissolve gallstones. Chenodeoxycholic acid can be used in the treatment of cerebrotendineous xanthomatosis. The Australian biotechnology company Giaconda has tested a treatment for Hepatitis C infection that combines chenodeoxycholic acid with bezafibrate.〔(【引用サイトリンク】title=Press release )〕 As diarrhea is a complication of chenodeoxycholic acid therapy, it has also been used to treat constipation. In supramolecular chemistry, molecular tweezers based on a chenodeoxycholic acid scaffold is a urea receptor that can contain anions in its binding pocket in order of affinity: H2PO4− (dihydrogen phosphate) > Cl− > Br− > I− reflecting their basicities (tetrabutylammonium counter ion).〔 Ki Soo Kim, Hong-Seok Kim ''Molecular Tweezer Based on Chenodeoxycholic Acid:Synthesis, Anion Binding Properties.'' Bulletin of the Korean Society 1411-1413 2004 (Article )〕 : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「chenodeoxycholic acid」の詳細全文を読む スポンサード リンク
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