[Functional state of a sphingomyeline cycle and free radical lipid oxidation activity of a rat's liver during different phases of starvation].

The functional state of a sphingomyeline cycle and character of its mutual relations with the processes of free radical lipid oxidation during starvation of animals without any restriction of access to drinking water at 1, 2, 3 day (I phase) and 6 day (II phase of starvation) were studied at the liver of rats. The maximal values of the ceramide/sphingomyeline ratio and activity neutral sphingomyelinase and executive caspase-3 were reached in a liver of animals at the 3rd day of starvation. From the 3rd day of starvation the concentration of the tumour necrosis factor-alpha which is one of activators neutral sphingomyelinase was increase in rats blood serum.

[Activity of the sphingomyelin cycle enzymes and concentration of products of sphingomyelin degradation in the rat liver in the course of acute toxic hepatitis].

Activity of key enzymes of a sphingomyelin cycle and the maintenance of its components (sphingomyelin, ceramide and sphingosine-1-phosphate) have been studied in livers of rats in dynamics of the acute toxic hepatitis caused by hypodermic introduction of an oil solution of CCl4. Sphingomyelinase activity significally increased already on early terms and remained increased over the whole period of observation. Activity of ceramidase insignificantly differed from the control level.

Activity of sphingomyelinase in rat liver in acute and chronic toxic hepatitis: proportion between peroxidative and phospholipase pathways of lipid bilayer modification.

We showed that sphingomyelinase activity in the liver increased only during the acute phase of toxic hepatitis. Peroxidative modification of hepatocyte membrane bilayer prevailed during the acute phase, while after transformation of the process to the chronic phase phospholipase pathway predominated.

Functional activity of sphingomyelin cycle in rat liver in chronic toxic hepatitis.

Activities of sphingomyelinase and ceramidase decreased in the liver in chronic toxic hepatitis and the balance between the levels of proapoptotic ceramide and antiapoptotic sphyngosine-1-phosphate shifts towards the latter substance. Pronounced changes in the qualitative and quantitative composition of fatty acids in the sphingomyelin cycle effector molecules were revealed.