Bile Acids


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Bile Acids

 

steroid monocarboxylic acids, derivatives of cholanic acid that are formed in the liver of man and animals and secreted with bile into the duodenum.

In the liver, bile acids are formed predominantly from cholesterol. Bile acids, which are present in different proportions in the bile of different animals, differ only in the number and spatial arrangement of their hydroxyl groups. Human bile contains principally cholic acid and small quantities of deoxycholic, lithocholic, and chenodeoxycholic acids. Very few bile acids are found in a free state in the bile; a large proportion of them are bound in the form of so-called conju-gate acids, such as glycocholic and taurocholic acid, which are formed as a result of the addition of bile acids to glycine and taurine.

Bile acids promote the digestion of fats in the intestinal tract; they activate the lipase of the pancreatic and intestinal juices and promote the emulsification of fats, stimulating their absorption in undecomposed form; they increase the speed of absorption of poorly soluble calcium salts of fatty acids by forming readily soluble complexes with them; and they greatly intensify intestinal peristalsis. In the intestinal tract a large proportion of the bile acid undergoes reverse absorption, and through the portal-vein system it enters the liver, where it is completely retained. The total bile-acid con-tent in the blood averages 0.8 mg percent; in the bile of the liver, 0.9–1.8 percent; and in cystic bile, 5.7–10.8 percent. When there is a considerable increase in the bile-acid content of the blood, the bile acids begin to be discharged with the urine. A decrease in bile-acid content is almost always accompanied by the precipitation of cholesterol, the principal constituent of gallstones.

G. A. SOLOV’EVA

References in periodicals archive ?
Cohort 2 is expected to broaden the evidence base for odevixibat by including PFIC patients who do not meet eligibility criteria for PEDFIC 1, but have elevated serum bile acid levels and pruritus.
They also got to know that it did not show any meaningful improvement in itch for most women, nor did it reduce the woman's bile acid levels.
Under the company's prior Phase 2 INDIGO clinical trial, the blocking bile acid transport from the intestine to the liver with maralixibat resulted in profound and durable reductions in serum bile acids (sBA), clinically meaningful improvements in pruritus and acceleration of growth in some patients with PFIC2.
Primary bile acids (synthesized from cholesterol in hepatocytes) include cholic and chenodeoxycholic acid.
Only the upper limit for bile acids could be calculated, as in 91% of the cases the concentration of bile acids was below the dynamic range of the rotor (35-200 [micro]mol/L).
The bile acids were quantified to determine whether there was a significant difference in their levels according to different ABCB11 1331T>C genotypes in HCV patients (Table 4).
Chiang, "Bile acids: regulation of synthesis," Journal of Lipid Research, vol.
Lepage, "Malabsorption of bile acids in children with cystic fibrosis," New England Journal of Medicine, vol.
Colonies were grown anaerobically [24] on blood agar plates (tryptic soy agar containing 5% sheep red blood cells) and used to inoculate BHI broth with or without 1 [micro]g/ml (0.3 [micro]M) of nisin or 100 [micro]g/ml (0.24 mM) of bile acids from Sigma-Aldrich, which contained 50% each of cholic and deoxycholic acid sodium salts.
Hofmann, "Bile acids: trying to understand their chemistry and biology with the hope of helping patients," Hepatology, vol.
Bile acids play their roles through specific receptors, including nuclear receptors [farnesoid X receptor (FXR), vitamin D receptor (VDR), and pregnane X receptor (PXR)] as well as membrane receptors [G-protein-coupled bile acid receptor 5 (TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and muscarinic receptor 2] [11-18], and may activate multiple signaling pathways [protein kinase B (AKT), extracellular regulated protein kinases (ERK1/2), and c-Jun N-terminal kinase (JNK)] [19-22].