Over the past few decades, a lot of new information about bile and its acids has been obtained. In this regard, it became necessary to revise and expand ideas about their significance for the life of the human body.
The role of bile acids. General information
The rapid development and improvement of research methods has made it possible to study bile acids in more detail. For example, there is now a clearer understanding of metabolism, their interaction with proteins, lipids, pigments and their content in tissues and fluids. Confirmed information indicates that bile acids are of great importance not only for the normal functioning of the gastrointestinal tract. These compounds are involved in many processes in the body. It is also important that, thanks to the use of the latest research methods, it was possible to most accurately determine how bile acids behave in the blood, as well as how they affect the respiratory system. Among other things, the compounds act on some parts of the central nervous system. Their importance in intracellular and externalmembrane processes. This is because bile acids act as surfactants in the internal environment of the body.
Historical facts
This type of chemical compounds was discovered by the scientist Strecker in the middle of the 19th century. He managed to find out that the bile of cattle has two organic acids. The first one contains sulfur. The second also contains this substance, but has a completely different formula. In the process of splitting these chemical compounds, cholic acid is formed. As a result of the transformation of the first compound mentioned above, glycerol is formed. At the same time, another bile acid forms a completely different substance. It's called taurine. As a result, the original two compounds were given names with the same names as the produced substances. This is how tauro- and glycocholic acid appeared, respectively. This discovery of the scientist gave a new impetus to the study of this class of chemical compounds.
Bile acid sequestrants
These substances are a group of drugs that have a lipid-lowering effect on the human body. In recent years, they have been actively used to lower blood cholesterol levels. This has significantly reduced the risk of various cardiovascular pathologies and coronary disease. At the moment, another group of more effective drugs is widely used in modern medicine. These lipid-lowering drugs are statins. They are used much more often due to fewer side effects.actions. At the present time, bile acid sequestrants are used less and less. Sometimes they are used exclusively as part of complex and supportive treatment.
Details
The steroid class includes monocarbaic hydroxy acids. They are active solids that are poorly soluble in water. These acids result from the processing of cholesterol by the liver. In mammals, they consist of 24 carbon atoms. The composition of the dominant bile compounds in different animal species is different. These types form taucholic and glycolic acids in the body. Chenodeoxycholic and cholic compounds belong to the class of primary compounds. How are they formed? In this process, liver biochemistry matters. Primary compounds arise from the synthesis of cholesterol. Next, the conjugation process takes place together with taurine or glycine. These types of acids are then secreted into the bile. Lithocholic and deoxycholic substances are part of the secondary compounds. They are formed in the large intestine from primary acids under the influence of local bacteria. The rate of absorption of deoxycholic compounds is much higher than that of lithocholic compounds. Other secondary bile acids occur in very small amounts. For example, ursodeoxycholic acid is one of them. If chronic cholestasis occurs, then these compounds are present in large quantities. The normal ratio of these substances is 3:1. While with cholestasis, the content of bile acids is considerably exceeded. Micelles are aggregatesfrom their molecules. They are formed only when the concentration of these compounds in an aqueous solution exceeds the limit mark. This is because bile acids are surfactants.
Features of cholesterol
This substance is poorly soluble in water. The rate of solubility of cholesterol in bile depends on the ratio of lipid concentration, as well as the molar concentration of lecithin and acids. Mixed micelles arise only when the normal proportion of all these elements is maintained. They contain cholesterol. The precipitation of its crystals is carried out under the condition of violation of this ratio. The functions of bile acids are not limited to removing cholesterol from the body. They promote the absorption of fats in the intestines. Micelles are also formed during this process.
Connection movement
One of the main conditions for the formation of bile is the active movement of acids. These compounds play an important role in the transport of electrolytes and water in the small and large intestines. They are solid powders. Their melting point is quite high. They have a bitter taste. Bile acids are poorly soluble in water, while they are good in alkaline and alcoholic solutions. These compounds are derivatives of cholanic acid. All such acids occur exclusively in cholesterol hepatocytes.
Influence
S alts are the most important among all acidic compounds. This isdue to a number of properties of these products. For example, they are more polar than free bile s alts, have a small micelle concentration limit, and are secreted faster. The liver is the only organ capable of converting cholesterol into specific cholanic acids. This is due to the fact that the enzymes that take part in conjugation are contained in hepatocytes. The change in their activity is directly dependent on the composition and rate of fluctuations of the bile acids of the liver. The synthesis process is regulated by a negative feedback mechanism. This means that the intensity of this phenomenon is in proportion to the current of secondary bile acids in the liver. The rate of their synthesis in the human body is quite low - from two hundred to three hundred milligrams per day.
Main Tasks
Bile acids have a wide range of uses. In the human body, they mainly carry out the synthesis of cholesterol and affect the absorption of fats from the intestines. In addition, the compounds are involved in the regulation of bile secretion and bile formation. These substances also have a strong influence on the process of digestion and absorption of lipids. Their compounds are collected in the small intestine. The process occurs under the influence of monoglycerides and free fatty acids, which are on the surface of fatty deposits. In this case, a thin film is formed, which prevents the connection of small drops of fat into larger ones. As a result, the surface tension is greatly reduced. This leads toformation of micellar solutions. They, in turn, facilitate the action of pancreatic lipase. With the help of a fatty reaction, it breaks them down into glycerol, which is then absorbed by the intestinal wall. Bile acids combine with fatty acids that do not dissolve in water and form choleic acids. These compounds are readily cleaved and rapidly absorbed by the villi of the upper small intestine. Choleic acids are converted into micelles. Then they are absorbed into the cells, while easily overcoming their membranes.
The latest research information in this area has been received. They prove that the relationship between fatty and bile acids in the cell breaks down. The former are the end result of lipid absorption. The latter - through the portal vein penetrate the liver and blood.
