INHIBITION OF CHOLESTEROL FORMATION BY RAT LIVER HOMOGENATES

1955 ◽  
Vol 33 (2) ◽  
pp. 135-138 ◽  
Author(s):  
B. B. Migicovsky
Keyword(s):  
Vitamin A ◽  
Rat Liver ◽  
Cholesterol Synthesis ◽  
Liver Homogenate ◽  
Inhibitory Factor ◽  
Normal Rat ◽  
Liver Homogenates

The inability of liver homogenates, from starved and vitamin A deficient rats, to synthesize cholesterol is illustrated. A possible reason for this phenomenon is that these preparations inhibit cholesterol synthesis when added to a liver homogenate from a normal rat. The inhibitory factor or factors are present in both the supernate and residue portions of the homogenate, although the residue matter is more inhibitory.

INHIBITION OF CHOLESTEROL FORMATION BY RAT LIVER HOMOGENATES

1955 ◽  
Vol 33 (1) ◽  
pp. 135-138 ◽  
Author(s):  
B. B. Migicovsky
Keyword(s):  
Vitamin A ◽  
Rat Liver ◽  
Cholesterol Synthesis ◽  
Liver Homogenate ◽  
Inhibitory Factor ◽  
Normal Rat ◽  
Liver Homogenates

The inability of liver homogenates, from starved and vitamin A deficient rats, to synthesize cholesterol is illustrated. A possible reason for this phenomenon is that these preparations inhibit cholesterol synthesis when added to a liver homogenate from a normal rat. The inhibitory factor or factors are present in both the supernate and residue portions of the homogenate, although the residue matter is more inhibitory.

Effect of Aureomycin on the Respiration of Normal Rat Liver Homogenates

Science ◽  
1951 ◽  
Vol 113 (2932) ◽  
pp. 273-273
Author(s):  
J. C. Van Meter ◽  
J. J. Oleson
Keyword(s):  
Rat Liver ◽  
Normal Rat ◽  
Liver Homogenates

EFFECT OF ALLOXAN, INSULIN, AND THYROXINE ON CHOLESTEROL AND FATTY ACID SYNTHESIS BY RAT LIVER HOMOGENATES

1957 ◽  
Vol 35 (1) ◽  
pp. 15-23 ◽  
Author(s):  
J. F. Scaife ◽  
B. B. Migicovsky
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthesis ◽  
Sodium Acetate ◽  
Cholesterol Synthesis ◽  
Acid Synthesis ◽  
Liver Homogenates ◽  
Vitro Effect

The in vitro effect of alloxan and insulin on the synthesis of cholesterol and fatty acids from 1-C14-sodium acetate by rat liver homogenates has been examined. Alloxan caused a reduction in the incorporation of acetate into cholesterol, fatty acids, and C14O2, but an increase in the oxygen consumption and carbon dioxide production. The addition of insulin to homogenates caused a reduction in cholesterol synthesis but an increase in fatty acid synthesis both for normal and diabetic animals. Homogenates from thyrotoxic rats exhibited a marked reduction in cholesterol synthesis when compared with normal animals. C14O2 production by homogenates from starved rats was appreciably lower than for those from normal animals. With this exception no appreciable difference was found in the oxygen uptake, carbon dioxide, or C14O2 production in homogenates from normal, starved, thyroxine-treated, or diabetic animals. Synthesized cholesterol was found to be located principally in the particulate matter of the homogenates after they had been incubated with 1-C14-sodium acetate. Homogenates from starved rats showed no greater tendency to degrade preformed cholesterol during incubation than did those from normal rats.

Different Expression of Esterase Variants in Rat Hepatic and Hepatom a-Derived Cell Lines Detected by Electrophoresis

1995 ◽  
Vol 50 (9-10) ◽  
pp. 664-668 ◽  
Author(s):  
Adel S. Afify ◽  
Yoshimitsu Yamazaki ◽  
Yu-ichi Kageyama ◽  
Shiro Yusa ◽  
Yoshikatsu Ogawa ◽  
...  
Keyword(s):  
Cell Lines ◽  
Rat Liver ◽  
Hepatoma Cell ◽  
Polyacrylamide Gel Electrophoresis ◽  
Liver Homogenate ◽  
Normal Liver ◽  
Liver Parenchyma ◽  
Hepatoma Cell Lines ◽  
Normal Rat ◽  
Transformed Cell Lines

Abstract Esterases in nine rat hepatic and hepatoma-derived cell lines and normal rat liver homogenate were detected by polyacrylamide gel electrophoresis coupled with active staining with a-naphthyl acetate or butyrate as a substrate. The esterase band patterns of the non-cancerous and oncogene-transformed cell lines were alike, but different from those of hepatoma cell lines and normal rat liver homogenate. The former groups of cells might have completely lost the characteristics of rat liver parenchymal cells, or else they might have their origin at cells other than liver parenchyma. The esterase patterns of the hepatoma cell lines (e.g., McA-RH7777) and the normal rat liver highly resembled with each other, exemplifying the slight biochemical deviation of cancer from normal cells. However, two-dimensional electrophoretogram for the McA-RH7777 cell line showed a prominent esterase spot {p/ 6.0-Mr 110 kDa) that was lacking in the normal liver. This result indicates that there is invariably some change in esterase expression between the cancer cells and the normal liver cells

EFFECT OF ALLOXAN, INSULIN, AND THYROXINE ON CHOLESTEROL AND FATTY ACID SYNTHESIS BY RAT LIVER HOMOGENATES

1957 ◽  
Vol 35 (1) ◽  
pp. 15-23 ◽  
Author(s):  
J. F. Scaife ◽  
B. B. Migicovsky
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthesis ◽  
Sodium Acetate ◽  
Cholesterol Synthesis ◽  
Acid Synthesis ◽  
Liver Homogenates ◽  
Vitro Effect

The in vitro effect of alloxan and insulin on the synthesis of cholesterol and fatty acids from 1-C14-sodium acetate by rat liver homogenates has been examined. Alloxan caused a reduction in the incorporation of acetate into cholesterol, fatty acids, and C14O2, but an increase in the oxygen consumption and carbon dioxide production. The addition of insulin to homogenates caused a reduction in cholesterol synthesis but an increase in fatty acid synthesis both for normal and diabetic animals. Homogenates from thyrotoxic rats exhibited a marked reduction in cholesterol synthesis when compared with normal animals. C14O2 production by homogenates from starved rats was appreciably lower than for those from normal animals. With this exception no appreciable difference was found in the oxygen uptake, carbon dioxide, or C14O2 production in homogenates from normal, starved, thyroxine-treated, or diabetic animals. Synthesized cholesterol was found to be located principally in the particulate matter of the homogenates after they had been incubated with 1-C14-sodium acetate. Homogenates from starved rats showed no greater tendency to degrade preformed cholesterol during incubation than did those from normal rats.

scholarly journals Aqueous Extracts of Teucrium polium Possess Remarkable Antioxidant Activity In Vitro

2006 ◽  
Vol 3 (3) ◽  
pp. 329-338 ◽  
Author(s):  
Predrag Ljubuncic ◽  
Suha Dakwar ◽  
Irina Portnaya ◽  
Uri Cogan ◽  
Hassan Azaizeh ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Antioxidant Activity ◽  
Rat Liver ◽  
Antioxidant Properties ◽  
Liver Homogenate ◽  
Plasma Oxidation ◽  
Teucrium Polium ◽  
Liver Homogenates ◽  
Β Carotene

Teucrium poliumL. (Lamiaceae) (RDC 1117) is a medicinal plant whose species have been used for over 2000 years in traditional medicine due to its diuretic, diaphoretic, tonic, antipyretic, antispasmodic and cholagogic properties. The therapeutic benefit of medicinal plants is often attributed to their antioxidant properties. We previously reported that an aqueous extract of the leaves and stems of this plant could inhibit iron-induced lipid peroxidation in rat liver homogenate at concentrations that were not toxic to cultured hepatic cells. Others have reported that organic extracts of the aerial components of this plant could inhibit oxidative processes. Against this background, we felt further investigation on the antioxidant action of the extract ofT. poliumprepared according to traditional Arab medicine was warranted. Accordingly, we assessed (i) its ability to inhibit (a) oxidation of β-carotene, (b) 2,2′-azobis(2-amidinopropan) dihydrochloride (AAPH)-induced plasma oxidation and (c) iron-induced lipid peroxidation in rat liver homogenates; (ii) to scavenge the superoxide ($${\hbox{ O }}_{2}^{\bullet -}$$) radical and the hydroxyl radical (OH•); (iii) its effects on the enzyme xanthine oxidase activity; (iv) its capacity to bind iron; and (v) its effect on cell glutathione (GSH) homeostasis in cultured Hep G2 cells. We found that the extract (i) inhibited (a) oxidation of β-carotene, (b) AAPH-induced plasma oxidation (c) Fe2+-induced lipid peroxidation in rat liver homogenates (IC50 = 7 ± 2 μg ml−1); (ii) scavenged $${\hbox{ O }}_{2}^{\bullet -}$$(IC50 = 12 ± 3 μg ml−1) and OH• (IC50 = 66 ± 20 μg ml−1); (iii) binds iron (IC50 = 79 ± 17 μg ml−1); and (iv) tended to increase intracellular GSH levels resulting in a decrease in the GSSG/GSH ratio. These results demonstrate that the extract prepared from theT. poliumpossesses antioxidant activityin vitro. Further investigations are needed to verify whether this antioxidant effect occursin vivo.

Diminished hepatic triiodothyronine production in Gunn rats

1986 ◽  
Vol 113 (2) ◽  
pp. 281-288 ◽  
Author(s):  
J. R. Saltzman ◽  
D. W. Clark ◽  
R. D. Utiger
Keyword(s):  
Thyroid Hormone ◽  
Rat Liver ◽  
Liver Homogenate ◽  
Unconjugated Bilirubin ◽  
Thyroid Hormone Metabolism ◽  
Gunn Rats ◽  
Deiodinase Activity ◽  
Sediment Fraction ◽  
Liver Homogenates

Abstract. The liver is a major site of conversion of thyroxine (T4) to the more active thyroid hormone 3,5,3'-triiodothyronine (T3). Hepatic T4 to T3 conversion is altered by a variety of pathological processes and pharmacological agents. We studied T4 to T3 conversion in glucuronyl transferase deficient homozygous Gunn rats because they have a hepatic enzyme abnormality which leads to hyperbilirubinaemia, and also because they have been reported to have alterations in thyroid hormone metabolism. An in vitro incubation system employing the 10 000 × g supernatant of liver homogenate was used, and T3 production was measured by radioimmunoassay. Experiments were done using substrate concentrations ranging from 0.56 to 20 μm, tissue protein in concentrations ranging from 0.625 to 20 mg and incubation times of 15 to 60 min. T3 production by liver homogenates from homozygous Gunn rats in these studies ranged from 29 to 70% of that produced by liver homogenates from phenotypically normal heterozygous Gunn rats. The deficit in hepatic T3 production by homozygous rats could not be overcome by increasing cofactor concentrations. After ultracentrifugation at 100 000 μ g, T4-5'-deiodinase activity was found primarily in the 100 000 × g sediment fraction. Homogygous rat liver 100 000 × g sediment T3 production was 55% of that of the heterozygous rat liver 100 000 × g sediment. Liver cytosol from both homozygous and heterozygous rats inhibited microsomal T4-5'-deiodinase activity similarly. Addition of unconjugated bilirubin to liver homogenates resulted in reduction of T3 production in livers from both homozygous and heterozygous rats. Thus the diminished capacity for hepatic conversion of T4 to T3 in homozygous Gunn rats may be due to inhibition of T4-5'-deiodinase activity by high endogenous levels of unconjugated bilirubin.

Vitamin A-poor lipocytes: a novel desmin-negative lipocyte subpopulation, which can be activated to myofibroblasts

1995 ◽  
Vol 269 (4) ◽  
pp. G532-G541 ◽  
Author(s):  
G. A. Ramm ◽  
R. S. Britton ◽  
R. O'Neill ◽  
W. S. Blaner ◽  
B. R. Bacon
Keyword(s):  
Vitamin A ◽  
Rat Liver ◽  
Smooth Muscle Actin ◽  
Cell Types ◽  
Receptor Expression ◽  
Alpha Smooth Muscle Actin ◽  
Hepatic Fibrogenesis ◽  
Quiescent Cells ◽  
Isolation And Characterization ◽  
Normal Rat

Lipocytes have been classified as vitamin A-storing, desmin-positive cells. In hepatic fibrogenesis, lipocytes transform into myofibroblasts, which express alpha-smooth muscle actin (alpha-SMA) and produce increased amounts of collagen. We isolated a population of vitamin A-poor lipocytes (VAPL) from normal rat liver and examined the morphological and biochemical differences between VAPL and vitamin A-replete lipocytes (VARL). Desmin and alpha-SMA expression were determined by Western blot in quiescent cells and in cells activated by culture on uncoated plastic. Both cell types were alpha-SMA-negative; however, in contrast to VARL, freshly isolated VAPL did not contain desmin. Desmin expression was induced in VAPL on activation. With time in culture, both VAPL and VARL expressed alpha-SMA and produced collagen, indicative of transformation to myofibroblasts. Ferritin receptor expression was demonstrated in cultured VARL after 1 day and in VAPL after 5 days, indicating that this is an early marker of lipocyte activation. After 7 days, VARL and VAPL were indistinguishable in terms of desmin, ferritin receptor expression, and collagen production. This study demonstrates the first isolation and characterization of two distinct quiescent subpopulations of lipocytes from normal rat liver: desmin-negative VAPL and desmin-positive VARL. Both populations of cells can be activated to myofibroblasts, the phenotype associated with hepatic fibrogenesis.

Effect of Aureomycin on the Respiration of Normal Rat Liver Homogenates

Science ◽  
1951 ◽  
Vol 113 (2932) ◽  
pp. 273-273 ◽  
Author(s):  
J. C. Van Meter ◽  
J. J. Oleson
Keyword(s):  
Rat Liver ◽  
Normal Rat ◽  
Liver Homogenates
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