Aquaporin expression and cholesterol content in eel swimbladder tissue

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.

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Hypersensitivity to Thromboxane A2 in Cholesterol-Rich Human Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647364 ◽

1990 ◽

Vol 64 (04) ◽

pp. 594-599 ◽

Cited By ~ 16

Author(s):

Takuya Tomizuka ◽

Kyohei Yamamoto ◽

Aizan Hirai ◽

Yasushi Tamura ◽

Sho Yoshida

Keyword(s):

Calcium Concentration ◽

Binding Capacity ◽

Thromboxane A2 ◽

Cytosolic Calcium ◽

Cholesterol Content ◽

Human Platelets ◽

Dissociation Rate ◽

Platelet Membrane ◽

Maximal Concentration ◽

Equilibrium Dissociation

SummaryThe effect of changes in platelet membrane cholesterol content on thromboxane A2 (TXA2)-induced platelet activation was studied. Concentrations of 9,ll-epithio-ll,12-methano-TXA2 (STA2), a stable analogue of TXA2 which can cause half-maximal aggregation and release of [14C]serotonin in cholesterol-rich platelets were significantly lower than those in cholesterol-normal platelets. STA2-induced increase in cytosolic calcium concentration and [32P]phosphatidic acid formation in cholesterol-rich platelets were significantly greater than those in cholesterol-normal platelets. The maximal concentration of binding site (Bmax) for SQ29548 was significantly increased in cholesterol-rich platelets compared with cholesterol-normal platelets, while the equilibrium dissociation rate constant (Kd) for SQ29548 did not differ between cholesterol-rich and cholesterol-normal platelets. The present study suggested that sensitivity to TXA2 was increased by the incorporation of cholesterol into platelet membrane and that the cause of hypersensitivity to TXA2 in cholesterol-rich platelets may be partly explained by an increase in binding capacity for TXA2.

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Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657214 ◽

1982 ◽

Vol 48 (01) ◽

pp. 049-053 ◽

Cited By ~ 47

Author(s):

C G Fenn ◽

J M Littleton

Keyword(s):

Platelet Aggregation ◽

Lipid Composition ◽

Saturated Fatty Acids ◽

Calcium Ionophore ◽

Cholesterol Content ◽

Membrane Lipid ◽

Calcium Ionophore A23187 ◽

Ionophore A23187 ◽

Increased Sensitivity

SummaryEthanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.

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INVESTIGATIONS ON LIPID AND CHOLESTEROL CONTENT OF THE ADRENAL CORTEX OF RATS AFTER ADMINISTRATION OF PYRIDINE-4-CARBONIC ACID-(DEXAMETHASONE-21′-)ESTERS

Acta Endocrinologica ◽

10.1530/acta.0.049s072 ◽

1965 ◽

Vol 49 (3_Suppl) ◽

pp. S72

Author(s):

Heinz Ueberberg

Keyword(s):

Adrenal Cortex ◽

Carbonic Acid ◽

Cholesterol Content

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PERMEABILITY OF CELLS AND ITS IMPORTANCE IN ASSESSMENT OF FISHES AGE

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2019/1/70-73 ◽

1970 ◽

pp. 70-73

Author(s):

N. I. Maslova

Keyword(s):

Cholesterol Content ◽

The Body ◽

Cellular Structures ◽

Ratio Estimation ◽

Carbohydrate Diet ◽

Spawning Period ◽

Age Related ◽

Experimental Base ◽

Cellular Permeability ◽

Membrane Strength

The article presents analysis of material and results of their own studies on changes in the permeability of cellular structures, organs and tissues in carp, which is of great importance in determining age-related indicators. The cells permeability in liver and gonads estimation was carried out under the experimental base of VNIIR on two carp genotypes during the pre-spawning period. The carp groups taken for analysis differed significantly in their genotypes. In females of the Khrapunov group the fecundity was 2023.0 thousand units, while the number of oocytes filled with yolk was only 0.7%, in the Ostashevsky ones - 1370.0 thousand units and 8.6%, respectively. During estimation the chemical composition of the generative tissue in females and males it was established that the cholesterol and lecithin content in males is higher than that of females, while feeding dependence is observed, especially on the amount of protein in the diet. For example, in females on protein diet contained less glycogen in gonads than on females on carbohydrate diet. Lecithin and cholesterol are higher in males than in females, which corresponds to increasing the Gyurdy Ratio (estimation of cell membrane strength). In spermatogenesis the content of phospholipids and cholesterol in the liver was decreased less than during ovogenesis. This indicates a lower level of synthetic processes in the milts compared with the ovaries. The cholesterol content in sperm is higher than in caviar in 19.6 times, and phospholipids almost doubled. With increasing age, the Gyordy Ratio for caviar decreases, for sperm it increases, the percentage of caviar fertilization increases. As the body age metabolism deteriorates, cellular permeability decreases (the ratio of lecithin and cholesterol changes significantly). At the same time, the permeability of cells in different organs and tissues varies and depends on living conditions, especially feeding and to some extent on the origin. In fish the gross productivity decreases as growth slows down and more energy is spent on adaptation to environmental conditions.

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Cholesterol in Serum and Lipoprotein Fractions

Clinical Chemistry ◽

10.1093/clinchem/2.3.145 ◽

1956 ◽

Vol 2 (3) ◽

pp. 145-159 ◽

Cited By ~ 187

Author(s):

Joseph T Anderson ◽

Ancel Keys

Keyword(s):

Human Serum ◽

Total Cholesterol ◽

Filter Paper ◽

Room Temperature ◽

Paper Electrophoresis ◽

Cholesterol Content ◽

Intraindividual Variability ◽

Detailed Data ◽

The Stability ◽

Source Of Error

Abstract 1. Methods are described for the separation, by paper electrophoresis and by cold ethanol, of α- and β-lipoproteins in 0.1 ml. of serum, with subsequent analysis of cholesterol in the separated portions. 2. It is shown that both methods of separation yield separated fractions containing substantially the same amounts of cholesterol. 3. Detailed data are given on the errors of measurement for total cholesterol and for cholesterol in the separated lipoprotein fractions. 4. Studies are reported on the stability of cholesterol in stored serum and on paper electrophoresis strips. It is shown that simple drying on filter paper causes no change in cholesterol content and yields a product that is stable for many weeks at ordinary room temperature. 5. The sources of variability in human serum cholesterol values are examined and it is shown that spontaneous intraindividual variability is a much greater source of error than the errors of measurement with these methods.

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