Fatty acids and cholesterol in the liver cell nuclei of hibernating Yakutian ground squirrels.

The content of neutral lipids in tissue homogenates and liver cell nuclei of hibernating Yakutian ground squirrels was studied. In homogenates, hibernation increases the content of fatty acids and reduces the content of glycerides and cholesterol. When studying the liver cell nuclei of torpid winter ground squirrels, we detected a twofold increase in the content of fatty acids, cholesterol, and monoglycerides as compared to the "summer" ground squirrels.

Phospholipids of liver cell nuclei during hibernation of Yakutian ground squirrel.

In hibernating Yakutian ground squirrels S. undulatus, the content of total phospholipids in the nuclei of liver increased by 40% compared to that in animals in summer. In torpid state, the amount of sphingomyelin increased almost 8 times; phosphatidylserine, 7 times; and cardiolipin, 4 times.

[Lipids in nuclei of neocortex neurons and glia under CNS-syndrome in rats].

The effect of a local exposure of rat heads to X-ray radiation at a dose of 200 Gy on the number of phospho- lipids and neutral lipids in the nuclear fraction ofneocortex neurons and glia has been investigated A decrease in the amount ofphosphatidylinositol and an increase in sphingomyelin in neuronal nuclei occurred 2 h after irradiation at the time of repair of locomotive disorders. The amount of phosphatidylcholine and phosphati- dylinositol dropped, and the amount of sphingomyelin and cholesterol increased in the nuclei ofglial cells of the neocortex. Sphingomyelin, phosphatidylinositol, phosphatidylcholine and cholesterol of neuronal nuclei are involved in the dynamics of the CNS syndrome in mammals.

Lipids in mammalian hibernation and artificial hypobiosis.

Membrane lipids-phospholipids, fatty acids, and cholesterol-participate in thermal adaptation of ectotherms (bacteria, amphibians, reptiles, fishes) mainly via changes in membrane viscosity caused by the degree of fatty acids unsaturation, cholesterol/phospholipids ratio, and phospholipid composition. Studies of thermal adaptation of endotherms (mammals and birds) revealed the regulatory role of lipids in hibernation. Cholesterol and fatty acids participate in regulation of the parameters of torpor, gene expression, and activity of enzymes of lipid metabolism.

Lipids of nuclear fractions from neurons and glia of rat neocortex under conditions of artificial hypobiosis.

Lipid contents were studied in tissue and nuclei isolated from neurons and glia of neocortex of rats under conditions of normothermia and in the state of artificial hypobiosis caused by hypothermia-hypoxia-hypercapnia. Compared to the neocortex tissue, both nuclear fractions were fivefold impoverished in phospholipids and cholesterol and strongly enriched with mono- and diglycerides and fatty acids. The nuclear fractions from neurons and glia contained similar amounts of phospholipids, and only the cardiolipin content in the neuronal nuclei was lower than in the glial nuclei.

Ornithine decarboxylase activity in rat organs and tissues under artificial hypobiosis.

The influence of hypothermia-hypoxia-hypercapnia on ornithine decarboxylase (ODC, EC 4.1.1.

Membrane lipids and morphology of brain cortex synaptosomes isolated from hibernating Yakutian ground squirrel.

Synaptosomes were isolated from Yakutian ground squirrel brain cortex of summer and winter hibernating animals in active and torpor states. Synaptosomal membrane cholesterol and phospholipids were determined. The seasonal changes of synaptosomal lipid composition were found.

Role of lipids in the assembly of endoplasmic reticulum and dictyosomes in neuronal cells from the cerebral cortex of Yakutian ground squirrel (Citellus undulatus) during hibernation.

Phospholipids and cholesterol were assayed in homogenates and microsomal fractions from the cerebral cortex of summer-active, winter-torpid, and winter-active Yakutian ground squirrels (Citellus undulatus). Ultrastructural analysis of both microsomal fraction and intact neurons was performed by serial ultramicrotomy. The levels of sphingomyelin (SM), phosphatidylserine (PS), and phosphatidylethanolamine (PEA) were decreased in homogenates from the cerebral cortex of winter ground squirrels compared with the summer-active animals, while the levels of phosphatidylcholine (PC) and cardiolipin (CL) were increased.

Synthesis of lipids in isolated nuclei from rat thymus and liver cells.

Synthesis of lipids was studied in isolated nuclei from rat thymus and liver cells. On incubation of the isolated nuclei with [2-14C]acetate and [1-14C]glycerol, the label was intensively incorporated into phospholipids and with a significantly lower intensity into fatty acids and cholesterol. Only trace amounts of radioactivity were detected in the lipids of chromatin prepared from isolated thymus nuclei after their incubation, and this suggested that lipids were mainly synthesized on the nuclear membrane.

Nuclear and chromatin lipids: metabolism in normal and gamma-irradiated rats.

The data on nuclear and chromatin lipid metabolism are reviewed. The amount of neutral lipids and phospholipids in nuclei of rat thymus, liver and neocortex neuron as well as the amount of lipids in rat thymus and liver chromatin are described. The metabolic responses of nuclear and chromatin lipids from thymus to different doses and dose rates of gamma-irradiation of rats are discussed.

Nonmonotonous Changes in Metabolic Parameters of Tissues and Cells under Action of Ionizing Radiation on Animal.

A nonmonotonous relationship between changes of metabolic parameters of tissues and cells of animal and radiation dose were discussed. Under acute irradiation of animals the nonmonotonous dose-response curve for metabolic parameters of tissues and cells were found. The nonmonotonous dose-response curves of metabolic and functional tissues and cells parameters were also revealed upon chronic irradiation of animals at a low dose-rate.

Ornithine decarboxylase in organs of rat following chronic gamma-irradiation at low dose-rates.

Purpose: To investigate the consequence of continuous low dose-rate exposure to gamma-rays on ornithine decarboxylase (ODC EC 4.1.1.

The effect of ionizing radiation on lipid metabolism in lymphoid cells.

Lipid metabolism was studied in lymphoid tissues of rats after whole body irradiation with doses producing damage of different degrees to lymphoid cells (4-10 Gy). The content of free cholesterol, cholesterol esters, and total phospholipids was determined in peripheral blood lymphocytes and thymocytes 1-2 h after exposure. Simultaneously, the rate of in vitro incorporation of 2 14C-acetate into total lipids, phospholipids, and cholesterol of lymphoid cells was estimated.