scholarly journals Effects of Cytochrome P450 Inhibitors on Itraconazole and Fluconazole Induced Cytotoxicity in Hepatocytes

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Nhareet Somchit ◽  
Chong Sock Ngee ◽  
Azhar Yaakob ◽  
Zuraini Ahmad ◽  
Zainul Amiruddin Zakaria
Keyword(s):  
Cytochrome P450 ◽  
Liver Perfusion ◽  
Antifungal Drugs ◽  
Female Rats ◽  
Atp Levels ◽  
P450 Inhibitors ◽  
Hepatocyte Toxicity

Itraconazole and fluconazole have been reported to induce hepatotoxicity in patients. The present study was designed to investigate the role of cytochrome P450 inhibitors, SKF 525A, and curcumin pretreatment on the cytotoxicity of antifungal drugs fluconazole and itraconazole. For 3 consecutive days, female rats were administered daily SKF 525A or curcumin (5 and 25 mg/kg). Control rats received an equivalent amount of dosed vehicle. The animals were anaesthetized 24 hours after receiving the last dose for liver perfusion. Hepatocytes were then exposed to various concentrations of antifungal drugs. In vitro incubation of hepatocytes with itraconazole revealed significantly lower viability when compared to fluconazole as assessed by lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase activities. The cytotoxicity of itraconazole was enhanced when incubated with hepatocytes pretreated with SKF 525A. SKF 525A had no effects on the cytotoxicity of fluconazole. Curcumin failed to either increase or decrease the cytotoxicity of both antifungal drugs. ATP levels also showed significant decrease in both itraconazole and fluconazole incubated hepatocytes. However, SKF 525A pretreated hepatocytes had significantly lower ATP levels after itraconazole incubations. Collectively, these results confirm the involvement of cytochrome P450 in the cytoprotection in itraconazole induced hepatocyte toxicity. Differences of the effects of SKF 525A on the cytotoxicity induced by itraconazole and fluconazole may be due to the differences on the metabolism of each antifungal drug in vivo.

scholarly journals In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol

2011 ◽  
Vol 4 (2) ◽  
pp. 78-84 ◽  
Author(s):  
Galia Zamaratskaia ◽  
Martin Rasmussen ◽  
Isabelle Herbin ◽  
Bo Ekstrand ◽  
Vladimir Zlabek
Keyword(s):  
Cytochrome P450 ◽  
Inhibitory Effect ◽  
17Β Estradiol ◽  
Cyp2e1 Activity ◽  
High Concentrations ◽  
Testicular Steroids ◽  
Sexually Mature

In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol Sexually mature pigs are known to possess high concentrations of testicular steroids, which have been shown to change the activities of cytochrome P450 in vitro. The aim of the present study was to evaluate the regulation of CYP1A and CYP2E1 activity by the steroids dihydrotestosterone (DHT), 3β-androstenol, 17β-estradiol and 17α-estradiol. Catalytic activities of 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD) were used as markers of CYP1A activities, while p-nitrophenol hydroxylase (PNPH) was used as a marker of CYP2E1 activities. Of the steroids tested, only 17β-estradiol and 17α-estradiol inhibited EROD and MROD activities. This inhibition was observed when a steroid concentration of 100 μM was used, while lower concentrations showed no inhibitory effect. PNPH activities were inhibited only by 100 μM of 17β-estradiol. The significance of these results in vivo is unknown because inhibition was only found when concentrations of estrogens higher than physiological levels were used. Nevertheless, the results provided further evidence on the important role of estrogens in regulation of porcine cytochrome P450 activities.

scholarly journals Mitochondrial Metabolism as Target of the Neuroprotective Role of Erythropoietin in Parkinson’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 121
Author(s):  
Federica Rey ◽  
Sara Ottolenghi ◽  
Toniella Giallongo ◽  
Alice Balsari ◽  
Carla Martinelli ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Extracellular Acidification ◽  
Atp Levels ◽  
Transmission Electron ◽  
First Time ◽  
Glycolytic Rate

Existing therapies for Parkinson’s disease (PD) are only symptomatic. As erythropoietin (EPO) is emerging for its benefits in neurodegenerative diseases, here, we test the protective effect driven by EPO in in vitro (SH-SY5Y cells challenged by MPP+) and in vivo (C57BL/6J mice administered with MPTP) PD models. EPO restores cell viability in both protective and restorative layouts, enhancing the dopaminergic recovery. Specifically, EPO rescues the PD-induced damage to mitochondria, as shown by transmission electron microscopy, Mitotracker assay and PINK1 expression. Moreover, EPO promotes a rescue of mitochondrial respiration while markedly enhancing the glycolytic rate, as shown by the augmented extracellular acidification rate, contributing to elevated ATP levels in MPP+-challenged cells. In PD mice, EPO intrastriatal infusion markedly improves the outcome of behavioral tests. This is associated with the rescue of dopaminergic markers and decreased neuroinflammation. This study demonstrates cellular and functional recovery following EPO treatment, likely mediated by the 37 Kda isoform of the EPO-receptor. We report for the first time, that EPO-neuroprotection is exerted through restoring ATP levels by accelerating the glycolytic rate. In conclusion, the redox imbalance and neuroinflammation associated with PD may be successfully treated by EPO.

scholarly journals The role of cytochrome P450 enzymes in carcinogen activation and detoxication: an in vivo–in vitro paradox

2018 ◽  
Vol 39 (7) ◽  
pp. 851-859 ◽  
Author(s):  
Lindsay Reed ◽  
Volker M Arlt ◽  
David H Phillips
Keyword(s):  
Cytochrome P450 ◽  
Cytochrome P450 Enzyme ◽  
Cytochrome P450 Enzymes ◽  
Predominant Role ◽  
Enzyme Systems ◽  
P450 Enzyme

Cytochrome P450 enzyme systems have been widely used in vitro to determine the pathways of activation of procarcinogens, but paradoxically, these same enzymes can play a more predominant role in carcinogen detoxification in vivo.

Mechanism-based inactivation of hepatic cytochrome P450 2C6 and P450 3A1 following in vivo administration of 3,5-diethoxycarbonyl-1,4-dihydro-2,6-dimethyl-4-ethylpyridine to rats: differences from previously observed in vitro results

1994 ◽  
Vol 72 (4) ◽  
pp. 397-401 ◽  
Author(s):  
S. M. Kimmett ◽  
J. P. McNamee ◽  
G. S. Marks
Keyword(s):  
Cytochrome P450 ◽  
Competitive Inhibition ◽  
Female Rats ◽  
Male Rats ◽  
Hepatic Microsomes ◽  
In Vitro Effects ◽  
P450 Isozymes ◽  
In Vivo Administration

Using progesterone 21-hydroxylase as a selective substrate for P450 2C6 in phenobarbital-treated male rats, and androstenedione and progesterone 6β-hydroxylases as well as erythromycin N-demethylase as selective markers for P450 3A1 in dexamethasone-treated female rats, we have shown that these P450 isozymes undergo mechanism-based inactivation after in vivo administration of 3,5-diethoxycarbonyl-1,4-dihydro-2,6-dimethyl-4-ethylpyridine (4-ethyl DDC). These results differ from our previous studies where no inactivation was observed after in vitro administration of 4-ethyl DDC to rat hepatic microsomes. We show that the differences between the in vivo and in vitro effects of 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine (DDC) analogues are due to the presence of residual 4-ethyl DDC in the in vitro experiments causing time-independent competitive inhibition and obscuring observation of mechanism-based inactivation.Key words: 3,5-diethoxycarbonyl-1,4-dihydro-2,6-dimethyl-4-ethylpyridine, cytochrome P450, steroid hydroxylation, rat hepatic microsomes.

scholarly journals In vivo effect of diallyl sulfide and cimetidine on phenacetin metabolism and bioavailability in rat.

2002 ◽  
Vol 49 (1) ◽  
pp. 249-256 ◽  
Author(s):  
Mirosław M Szutowski ◽  
Katarzyna Zalewska ◽  
Marta Jadczak ◽  
Monika Marek
Keyword(s):  
Cytochrome P450 ◽  
Area Under The Curve ◽  
Diallyl Sulfide ◽  
Rat Serum ◽  
P Glycoprotein ◽  
Cytochrome P450 Isoforms ◽  
Inhibitory Efficiency ◽  
P450 Inhibitors

Numerous cytochrome P450 inhibitors have been described as effective modulators of cytochrome P450 isoforms activity in vitro. Their inhibitory efficiency may be considerably modified after in vivo application. The aim of this study was to examine the effect of oral administration of diallyl sulfide--a cytochrome P450 2E1 inhibitor and cimetidine--a cytochrome P450 2C6 and 2C11 inhibitor on rat serum concentration of phenacetin and its metabolite acetaminophen. Both inhibitors increased area under the curve (AUC(0-4 h)) for phenacetin by 50%. Only cimetidine reduced AUC(0-4 h) for acetaminophen indicating inhibition of O-deethylation activity. Quinidine--a cytochrome P450 2D subfamily and P-glycoprotein inhibitor did not change significantly phenacetin bioavailability. These results suggest that diallyl sulfide inhibits the deacetylation pathway catalysed by arylamine N-acetyl transferase. Beside cytochrome P450 1A2 other cytochrome P450 isoforms (2A6 and/or 2C11) are involved in phenacetin O-deethylation in rat.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Pharmacogenetics of Clozapine: In Vivo Role of Cytochrome P450 Isoforms and P-Glycoprotein

2008 ◽  
Vol 41 (05) ◽  
Author(s):  
E Jaquenoud-Sirot ◽  
B Knezevic ◽  
G Perla Morena ◽  
P Baumann ◽  
CB Eap
Keyword(s):  
Cytochrome P450 ◽  
P Glycoprotein ◽  
Cytochrome P450 Isoforms

Anti-obesity role of Aster glehni extract: in vivo and in vitro effects

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
HM Lee ◽  
TG Ahn ◽  
CW Kim ◽  
HJ An
Keyword(s):  
In Vitro Effects

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

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