scholarly journals ACTIVITY OF THE MICROSOMAL OXIDATION SYSTEM IN RAT LIVER UNDER THE INFLUENCE OF SODIUM FLUORIDE

2021 ◽  
pp. 121-124
Author(s):  
I. Yu. Bagmut ◽  
I. L. Kolisnyk
Keyword(s):  
Rat Liver ◽  
Sodium Fluoride ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
The Body ◽  
Endogenous Respiration ◽  
Monooxygenase System ◽  
Rat Liver Microsomes ◽  
Microsomal Oxidation ◽  
Fluoride Intoxication

Summary. The pathogenesis of fluoride intoxication at the molecular, cellular and functional levels has not been sufficiently studied. There are very few modern data on these issues, so they are contradictory, since the effects of this trace element are multifaceted and cannot be characterized unambiguously. The aim of the study – to learn the state of the monooxygenase system of rat hepatocytes under conditions of the formation of fluoride intoxication. Materials and Methods. In the experiment, we used 30 sexually mature rats (N=30) of the Wistar population weighing 200–210 g for 1.5 months. Sodium fluoride solution was administered orally at doses of 1/10 DL50, which was 20 mg/kg of animal body weight. Results. The results of experiments on the study of oxygen consumption by rat liver microsomes under fluoride intoxication indicated that the rate of endogenous respiration of microsomes, the rate of NADPH oxidation, the rate of NADH oxidation in the presence of EDTA, and the rate of lipid peroxidation increase under the influence of fluorides. Sodium fluoride stimulated an increase in all parameters of microsomal oxidation, except for cytochrome b5. It should be assumed that in this case there is an increase in the generation of reactive oxygen species, free radicals, which stimulate the development of free radical processes in the body and are, most likely, the leading link in oxidative stress. Conclusions. These changes indicate a violation of the bioenergetics of hepatocytes associated with the mitochondrial apparatus and the development of hypoxic processes, which lead to a decrease in the activity of redox reactions occurring at the level of intracellular membranes and organelles.

scholarly journals Inhibition of phosphatidylcholine synthesis by vasopressin and angiotensin in rat hepatocytes

1982 ◽  
Vol 208 (2) ◽  
pp. 453-457 ◽  
Author(s):  
S Alemany ◽  
I Varela ◽  
J M Mato
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
Rat Liver Microsomes ◽  
Isolated Rat Hepatocytes ◽  
Fast Transient ◽  
Phosphatidylcholine Synthesis ◽  
Isolated Rat

The addition of 1 microM-vasopressin or -angiotensin to isolated rat hepatocytes induced a fast transient inhibition of the rate of incorporation of [Me-3H]choline into phosphatidylcholine. The cationophore A23187 induced a similar inhibition of phosphatidylcholine synthesis. The addition of micromolar Ca2+ to rat liver microsomes inhibited the activity of CDP-choline: 1,2-diacylglycerol cholinephosphotransferase. This inhibition is due a decrease in the Vmax. of the enzyme without affecting the Km for CDP-choline. It is concluded that Ca2+ regulates phosphatidylcholine synthesis in rat liver.

A Direct, Highly Sensitive Fluorometric Assay for a Microsomal Cytochrome P450-Mediated O-Demethylation Using a Novel Coumarin Analog as Substrate

2000 ◽  
Vol 55 (11-12) ◽  
pp. 915-922 ◽  
Author(s):  
René Roser ◽  
Helmut Thomas
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
Fluorometric Assay ◽  
Excitation Wavelength ◽  
Monooxygenase System ◽  
Rat Liver Microsomes ◽  
Monooxygenase Activity ◽  
Continuous Increase ◽  
Highly Sensitive

A highly sensitive fluorometric assay for the determination of monooxygenase activity in liver microsomes is described. The assay is based on the use of 3-chloro-7-methoxy-4-methylcoumarin which is demethylated to 3-chloro-7-hydroxy-4-methylcoumarin. The rate of formation of 3-chloro-7-hydroxy-4-methylcoumarin was recorded as an increase of fluorescence (λA = 380 nm, λF = 480 nm ) with time. When 3-chloro-7-methoxy-4-methylcoumarin was incubated in the presence of MgCl2and NADPH with rat liver microsomes, a continuous increase of the fluorescence could be measured. The reaction proceeded linearly for about 10 min and at least up to a concentration of 0.1 mg/ml of microsomal protein. Besides 3-chloro-7-hydroxy-4-methylcoumarin a hydroxylated derivative of the substrate was formed as a second metabolite during the incubation. Using an excitation wavelength of 480 nm and a fluorescence/em ission w avelength of 480 nm, the fluorescence of this substance (λA = 338 nm, λF = 422 nm ) amounted only to about 1% of the fluorescence of the main product. The use of 3-chloro-7-methoxy-4-methylcoumarin as substrate enables the fluorometric determination of the O-dealkylation activity of a cytochrom e P450-dependent monooxygenase system in rat liver which is inducible by phenobarbital but not by 3-methylcholanthrene.

scholarly journals Evidence that a low-molecular-mass GTP-binding protein is required for store-activated Ca2+ inflow in hepatocytes

1997 ◽  
Vol 328 (2) ◽  
pp. 463-471 ◽  
Author(s):  
C. Kekulu FERNANDO ◽  
B. Roland GREGORY ◽  
Frosa KATSIS ◽  
E. Bruce KEMP ◽  
J. Greg BARRITT
Keyword(s):  
Endoplasmic Reticulum ◽  
Molecular Mass ◽  
G Protein ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Brefeldin A ◽  
Rat Hepatocytes ◽  
Rat Liver Microsomes ◽  
Isolated Rat Hepatocytes ◽  
Gtp Binding

The roles of a monomeric GTP-binding regulatory protein in the activation of store-activated plasma membrane Ca2+ channels and in the release of Ca2+ from the smooth endoplasmic reticulum (SER) in rat liver parenchymal cells were investigated with the use of freshly isolated rat hepatocytes and rat liver microsomes. A low concentration (approx. 130 μM intracellular) of guanosine 5ʹ-[γ-thio]triphosphate (GTP[S]) activated Ca2+ inflow in intact hepatocytes in the absence of an agonist, whereas a high concentration (approx. 530 μM intracellular) of GTP[S] or guanosine 5ʹ-[βγ-imido]triphosphate (p[NH]ppG) inhibited the Ca2+ inflow induced by inhibitors of the activity of the endoplasmic-reticulum Ca2+-ATPase (SERCA) and by vasopressin. GTP (530 μM) prevented the inhibition of Ca2+ inflow by GTP[S] and p[NH]ppG. Brefeldin A and the peptide human Arf-1-(2-17), which inhibit many functions of ADP ribosylation factor (Arf) proteins, inhibited the Ca2+ inflow induced by SERCA inhibitors and vasopressin, and altered the profile of Ca2+ release from the SER. These effects were observed at concentrations of Brefeldin A and Arf-1-(2-17) comparable with those that inhibit the functions of Arf proteins in other systems. Succinylated Arf-1-(2-17) had a negligible effect on Ca2+ inflow. GTP[S] and Arf-1-(2-17) completely inhibited the synergistic action of GTP and Ins(1,4,5)P3 in releasing 45Ca2+ from rat liver microsomes loaded with 45Ca2+. AlF4- (under conditions expected to activate trimeric G-proteins) and succinylated Arf-1-(2-17) had no effect on GTP/Ins(1,4,5)P3-induced 45Ca2+ release, and a mastoparan analogue caused partial inhibition. Arf-1-(2-17) did not inhibit 45Ca2+ release induced by either thapsigargin or ionomycin. It is concluded that a low-molecular-mass G-protein, most probably a member of the Arf protein family, is required for store-activated Ca2+ inflow in rat hepatocytes. The idea that the role of this G-protein is to maintain a region of the SER in the correct intracellular location is discussed briefly.

The stereoselective biotransformation of the anti-obesity drug sibutramine in rat liver microsomes and in primary cultures of rat hepatocytes

2005 ◽  
Vol 57 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Marek Link ◽  
Romana Novotná ◽  
Bohumila Suchanová ◽  
Lenka Skálová ◽  
Vladimír Wsól ◽  
...  
Keyword(s):  
Rat Liver ◽  
Primary Cultures ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
Rat Liver Microsomes

Characterization of enzymes responsible for biotransformation of the new antileukotrienic drug quinlukast in rat liver microsomes and in primary cultures of rat hepatocytes

2004 ◽  
Vol 56 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Barbora Szotáková ◽  
Lenka Skálová ◽  
Vendula Baliharová ◽  
Martina Dvorščaková ◽  
Lenka Štorkánová ◽  
...  
Keyword(s):  
Rat Liver ◽  
Primary Cultures ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
Rat Liver Microsomes

Influence of sulfur on the monooxygenase system of rat liver microsomes

1992 ◽  
Vol 26 (2) ◽  
pp. 128-131
Author(s):  
I. I. Romanovskaya ◽  
O. V. Sevast'yanov ◽  
T. I. Davidenko
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
Monooxygenase System ◽  
Rat Liver Microsomes

Induction of Cytochrome P-450-linked Monooxygenase System in Rat Liver Microsomes by Xiao-Chaihu-Tang

1996 ◽  
Vol 24 (02) ◽  
pp. 143-151 ◽  
Author(s):  
Taira Ohnishi ◽  
Hirohito Yoneyama ◽  
Tatushichiro Hamamoto ◽  
Toshihiko Ishida ◽  
Jirou Takahara ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
The Other ◽  
Female Rats ◽  
Male Rats ◽  
Monooxygenase System ◽  
Rat Liver Microsomes ◽  
Female Rat ◽  
Metabolic Rates ◽  
Cytochrome P 450

The administration of Xiao-Chaihu- Tang (TJ-9) for 2 weeks induced a 25% increase in the content of cytochrome P-450 in female rat liver microsomes, while the content in male rats remained unchanged. The enzymatic activities toward various xenobiotics were stimulated in female rats, the levels being in the range of 125-250% of those in the control rats. Among these xenobiotics, the metabolic rates for substrates of cytochrome P-450 2El were significantly enhanced in female rats. On the other hand, the activities toward various xenobiotics in male rats were unchanged. When 3-methylcholanthrene was given to rats for a week, the augmentation of cytochrome P-450 content and the stimulation ofxenobiotic metabolism were observed. However, co-administration ofTJ-9 did not alter the effect of 3-methylcholanthrene described above.

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