|
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ИНХС РАН |
||
[The different notions about beta-oxidation of fatty acids in peroxisomes, peroxisomes and ketonic bodies. The diabetic, acidotic coma as an acute deficiency of acetyl-CoA and ATP]статья
- Авторы: Kotkina T.I., Titov V.N., Parkhimovich R.M.
- Журнал: Klinicheskaia laboratornaia diagnostika
- Номер: 3
- Год издания: 2014
- Первая страница: 14
- Последняя страница: 23
- Аннотация: The mechanisms of beta-oxidation of fatty acids developed more than a century before have no compliance with actual physical chemical data. The oxidation of long-chain C 16:0 palmitic saturated fatty acid occurs not by sequential formation of eight molecules of acetyl-KoA but by force of formation of double bond and its hydrolysis on two short-chain C 8:0 fatty acids. Only short-chain fatty acids can become shorter under "chipping" of C 2-acetate with formation of C 4-butyric acid (butyrate) and its metabolites (beta-hidroxibutirate, acetoacetate, acetone). The critical moment of oxidation is a hydrolysis of acetoacetyl-KoA on two molecules of acetyl-KoA. The molecule of ATP is to be expended on hydrolysis. The foundation of nonspecific biological reaction of stress--ketoacidosis,--is a decrease in mitochondrions of acetyl-KoA pool formed both from glycogen and glucose and fatty acids. The oxalate acetate inputs into Krebs cycle inadequate amount of acetyl-KoA which limits synthesis of ATP. The insulin has no direct involvement into development of ketoacidosis but prepares conditions to facilitate nonspecific etiological factor to initiate diabetic ketoacidosis. These are the pooling of small amount of glycogen in cytozol and the predominance in cytozol of cells and adipocytes of palmitic triglycerides which are slowly hydrolyzed by hormone-dependent lipase to release non-esterified fatty acids into intercellular medium. The increase of their concentration in blood plasma precedes ketoacidosis which is developing in patients without diabetes mellitus too. When cells begin to oxidize unsaturated linoleic and linolenic acids with large number of double binds instead of medium-chain fatty acids, oleinic and palmitic fatty acids to support beta-oxidation in mitochondrions and synthesis of ATP the amount of butyric acid, beta-hidroxibutiryl-KoA and acetoacetyl-KoA increases and of acetyl-KoA decreases. The cause of fatal outcome is the development of metabolic acidosis, hyperhydration of cerebral cells with development of edema and a physiologic respiratory compensation of metabolic acidosis. The decarboxylation of acetoacetate and formation of acetone--initial stage of gluconeogenesis--formation of glucose from fatty acids--is manifested poorly both in primates and humans. From theoretical positions, to arrest ketoacidosis and to restore synthesis of AFT, it is reasonable to apply the infusion of optimal amount of acetyl-KoA which as nonpolar tioester can get over hematoencephalic barrier, plasma membrane and inner membrane of mitochondrions. It is supposed that diabetes mellitus is to be considered primarily as pathology of metabolism of fatty acids and only secondly as pathology of glucose.
- Добавил в систему: Титов Владимир Николаевич