Microsomal Oxidation Research Articles

The formation of knowledge on toxicants as the components of chemical safety for future doctors during their studies of bioorganic chemistry and biochemistry

Chemical safety of treating chemical substances is key problems that unite the international community. Realization of the modern model of chemical safety provides the coordinated work of legal, economic, ecological-hygienic, prophylactic and educational components. A doctor of ХХІ century must have knowledge about modern approaches to classification of dangers and marking chemical substances, be able to ground toxicological properties and molecular mechanisms of the effect of toxicants, estimate risks as to using chemical substances of inorganic and organic nature, give medical care to persons, who suffered as a result of the influence of chemical compounds. The paper theoretically grounds methodical approaches to formation of knowledge about inorganic toxicants as a component of chemical safety in future doctors at studying bioorganic and biological chemistry. There is presented the analysis of the learning program on biological chemistry, and it was established, that formation of knowledge about inorganic toxicants as a component of chemical safety can be realized at studying such topics as enzymes, bases of bioenergetics, metabolism of amino acids, bases of molecular genetics, biochemistry of human nutrition, biochemistry of blood and liver. It was proved, that “Biochemistry of the liver” is a generalizing section as to problems of chemical safety in the course of bioorganic and biological chemistry. The structural-logic scheme of formation of knowledge about dangerous chemical substances is described. There was realized the purposeful pedagogical influence as formation of knowledge about organic and inorganic toxicants as components of chemical safety, in the course of “Bioorganic and biological chemistry” at studying the topic “Investigation of processes of biotransformation of xenobiotics and endogenous toxins. Microsomal oxidation by cytochrome Р-450”. There were developed two video-collections “Modern approaches to classification and marking of chemical substances”, “Biotransformation of xenobiotics and endogenous toxins” and cases “Toxicants in the context of chemical safety”. The developed materials were probated in the course of biological chemistry at training future doctors in the National medical university, named after O.O. Bogomolets

CYP3A4 gene polymorphism is correlated with individual consumption of sufentanil.

Pain is one of the major adverse clinical outcomes of cesarean section (CS). In the past few years, researchers and physicians have been optimizing post-operative analgesic modalities, but the results are still undesirable for the parturient. The cytochrome P-450 3A4 (CYP3A4) gene has been reported to contribute significantly to human liver microsomal oxidation of sufentanil and alfentanil. We detected the frequency of CYP3A4 mutant allele, which is associated with the metabolism of diverse drugs, including opioids used for anesthesia. We then investigated the correlation between sufentanil (an opioid analgesic) consumption and CYP3A4 genetic polymorphism. We found the frequency of the CYP3A4∗1G (the mutant form of CYP3A) variant allele to be 0.279 in 71 parturients undergoing cesarean section and 137 age-matched parturients with vaginal delivery. Interestingly, the parturients with homozygous CYP3A4∗1G showed less sufentanil consumption compared with those having the wild-type genotype. In summary, we found a correlation between CYP3A4 genetic polymorphism and sufentanil consumption. This might be helpful for optimizing the anesthesia strategies and reducing their side effects.

2-Mercapto-Quinazolinones as Inhibitors of Type II NADH Dehydrogenase and Mycobacterium tuberculosis: Structure-Activity Relationships, Mechanism of Action and Absorption, Distribution, Metabolism, and Excretion Characterization.

Mycobacterium tuberculosis (MTb) possesses two nonproton pumping type II NADH dehydrogenase (NDH-2) enzymes which are predicted to be jointly essential for respiratory metabolism. Furthermore, the structure of a closely related bacterial NDH-2 has been reported recently, allowing for the structure-based design of small-molecule inhibitors. Herein, we disclose MTb whole-cell structure–activity relationships (SARs) for a series of 2-mercapto-quinazolinones which target the ndh encoded NDH-2 with nanomolar potencies. The compounds were inactivated by glutathione-dependent adduct formation as well as quinazolinone oxidation in microsomes. Pharmacokinetic studies demonstrated modest bioavailability and compound exposures. Resistance to the compounds in MTb was conferred by promoter mutations in the alternative nonessential NDH-2 encoded by ndhA in MTb. Bioenergetic analyses revealed a decrease in oxygen consumption rates in response to inhibitor in cells in which membrane potential was uncoupled from ATP production, while inverted membrane vesicles showed mercapto-quinazolinone-dependent inhibition of ATP production when NADH was the electron donor to the respiratory chain. Enzyme kinetic studies further demonstrated noncompetitive inhibition, suggesting binding of this scaffold to an allosteric site. In summary, while the initial MTb SAR showed limited improvement in potency, these results, combined with structural information on the bacterial protein, will aid in the future discovery of new and improved NDH-2 inhibitors.

Differential effects of hepatic cirrhosis on the intrinsic clearances of sorafenib and imatinib by CYPs in human liver

The tyrosine kinase inhibitors sorafenib and imatinib are important in the treatment of a range of cancers but adverse effects in some patients necessitate dosage modifications. CYP3A4 has a major role in the oxidation of sorafenib to its N-oxide and N-hydroxymethyl metabolites and also acts in concert with CYP2C8 to mediate imatinib N-demethylation. CYP3A4 expression and function are impaired in patients with advanced liver disease, whereas the functions of CYP2C enzymes are relatively preserved. We evaluated the biotransformation of sorafenib and imatinib in well-characterized microsomal fractions from 17 control subjects and 19 individuals with hepatic cirrhosis of varying severity. The principal findings were that liver disease impaired the microsomal oxidation of sorafenib to its major metabolites to 40–44% of control (P<0.01), whereas the N-demethylation of imatinib was relatively unimpaired. The impairments in sorafenib biotransformation were correlated with decreased serum albumin concentrations and increased serum bilirubin concentrations in patients with liver disease, but not with the overall grade of liver disease according to the Child-Pugh system. In contrast, there was no relationship between imatinib N-demethylation and clinicopathologic factors in liver disease patients. These findings were accounted for in terms of the differential roles of CYPs 3A4 and 2C8 in the intrinsic clearance of the drugs. CYP3A4 has the major role in the intrinsic clearance of sorafenib but plays a secondary role to CYP2C8 in the intrinsic clearance of imatinib. In agreement with these findings CYP2C protein expression and CYP2C8-mediated paclitaxel 6α-hydroxylation were unimpaired in cirrhotic livers. This information could be adapted in individualized approaches such as in vivo CYP3A4 phenotyping to optimize sorafenib safety and efficacy in cancer patients with liver dysfunction.

Electrochemical versus Enzymatic in Vitro Oxidations of 6-propyl-2-thiouracil: Identification, Detection, and Characterization of Metabolites.

6-Propylthiouracil, PTU, is a well-known antithyroid drug that has been the mainstay of treatment of Graves' disease. It is, however, also associated with liver toxicity and idiosyncratic toxicity. These toxicities are generally associated with metabolites derived from its bioactivation. In this manuscript, bioactivation of PTU was studied via two separate techniques: electrochemical oxidation and through the use of human liver microsomes. The aim of this work was to compare the bioactivation products of these two techniques. The electrochemical technique was studied online with a mass spectrometer, EC/ESI/MS. The microsomal oxidations were studied in tandem with liquid chromatography. The EC/ESI/MS technique was devoid of the normal reducing biological matrix prevalent in microsomal incubations. The predominant product at 400 mV was the dimeric PTU species with negligible formation of other metabolites. At higher potentials, complete desulfurization of PTU was observed with formation of sulfate. No sulfonic acid was observed, suggesting that the cleavage of the C-S bond was effected at the sulfinic acid stage, releasing a highly reducing sulfur species which is known to give rise to genotoxicity. The microsomal oxidations, surprisingly, showed formation of the unstable sulfenic acid, the S-oxide. Further incubation showed both the sulfinic and sulfonic acids. None of the systems showed any adducts with nucleophiles such as glutathione, showing that none of the reactive metabolites were stable enough to be adducted to nucleophiles in both the biological matrix and the electrochemical oxidizing environment.

The Role of CYP1A1 Gene Polymorphism in Patients with Erysipelas

The research aims are to study the role of CYP1A1 gene polymorphism in predisposition to erysipelas and reveal connections with the clinical course of the disease. We used the standard techniques of molecular genetic analysis. The DNA samples used in genotyping were extracted from leukocytes of venous blood by deproteinization with a phenol-chloroform mixture. Genotyping was performed by polymerase chain reaction (PCR). Statistical data relating to the investigated polymorphic markers were estimated at a 95% confidence level (CL). Genotype frequencies were compared using either the standard Pearson’s chi-squared test or the two-sided Fisher’s exact test. This study presents a comparative analysis of the distribution of gene polymorphisms of cytochrome P450 CYP1A1 (Ile462Val, rs1048943) of phase I detoxification (microsomal oxidation) in the experimental group of 71 patients with erysipelas and a control group of 71 healthy individuals. We also analyzed these relationships of CYP1A1 (Ile462Val) gene polymorphisms with the sex of the patients, the severity and multiplicity of the disease, and the nature of the local process in patients with erysipelas. The results of the investigation indicate the presence of a relationship between cytochrome P450 CYP1A1 (Ile462Val, rs1048943) gene polymorphism and the development of erysipelas. Analysis of these relationships of CYP1A1 (Ile462Val) gene polymorphism with the sex of the patients, the severity and multiplicity of the disease, and the nature of the process in the examined group of patients with erysipelas did not reveal any statistically significant differences.

Regio- and Stereo-Selective Oxidation of a Cardiovascular Drug, Metoprolol, Mediated by Cytochrome P450 2D and 3A Enzymes in Marmoset Livers.

A β-blocker, metoprolol, is one of the in vivo probes for human cytochrome P450 (P450) 2D6. Investigation of nonhuman primate P450 enzymes helps to improve the accuracy of the extrapolation of pharmacokinetic data from animals into humans. Common marmosets (Callithrix jacchus) are a potential primate model for preclinical research, but the detailed roles of marmoset P450 enzymes in metoprolol oxidation remain unknown. In this study, regio- and stereo-selectivity of metoprolol oxidations by a variety of P450 enzymes in marmoset and human livers were investigated in vitro. Although liver microsomes from cynomolgus monkeys and rats preferentially mediated S-metoprolol O-demethylation and R-metoprolol α-hydroxylation, respectively, those from humans, marmosets, minipigs, and dogs preferentially mediated R-metoprolol O-demethylation, in contrast to the slow rates of R- and S-metoprolol oxidation in mouse liver microsomes. R- and S-metoprolol O-demethylation activities in marmoset livers were strongly inhibited by quinidine and ketoconazole, and were significantly correlated with bufuralol 1'-hydroxylation and midazolam 1'-hydroxylation activities and also with P450 2D and 3A4 contents, which is different from the case in human livers that did not have any correlations with P450 3A-mediated midazolam 1'-hydroxylation. Recombinant human P450 2D6 enzyme and marmoset P450 2D6/3A4 enzymes effectively catalyzed R-metoprolol O-demethylation, comparable to the activities of human and marmoset liver microsomes, respectively. These results indicated that the major roles of P450 2D enzymes for the regio- and stereo-selectivity of metoprolol oxidation were similar between human and marmoset livers, but the minor roles of P450 3A enzymes were unique to marmosets.

The role of microsomal oxidation in the regulation of monoamine oxidase activity in the brain and liver of rats

It has been shown in our previous study that monoamine oxidase (MAO) activity in different brain regions are correlated with a microsomal oxidation phenotype. The data obtained in this study, using the microsomal oxidation inhibitor SKF525, and using animals with different duration of hexobarbital sleep, has shown that increased intensity of microsomal oxidation might be associated with increased MAO activity. Since the rats with short hexobarbital sleep time had higher content of hepatic microsomal cytochrome P450 than did rats with long hexobarbital sleep time. In addition, the rats with higher hepatic content of CYP450 had higher activities of MAO-A and MAO-B. Moreover, the microsomal oxidation inhibitor SKF-525 reduced brain and liver activities of MAOA and MAO-B. Consequently, MAO activities in a brain and a liver depend on the microsomal oxidation process.

Role of Microsomal Oxidation in Regulation of Monoamine Oxidase Activity in Rat Brain and Liver

Role of Microsomal Oxidation in Regulation of Monoamine Oxidase Activity in Rat Brain and Liver

Attenuation of the liver microsomal oxidation in experimental posttraumatic stress disorders

Attenuation of the liver microsomal oxidation in experimental posttraumatic stress disorders

Species Differences in Microsomal Oxidation and Glucuronidation of 4-Ipomeanol: Relationship to Target Organ Toxicity.

4-Ipomeanol (IPO) is a model pulmonary toxicant that undergoes P450-mediated metabolism to reactive electrophilic intermediates that bind to tissue macromolecules and can be trapped in vitro as the NAC/NAL adduct. Pronounced species and tissue differences in IPO toxicity are well documented, as is the enzymological component of phase I bioactivation. However, IPO also undergoes phase II glucuronidation, which may compete with bioactivation in target tissues. To better understand the organ toxicity of IPO, we synthesized IPO-glucuronide and developed a new quantitative mass spectrometry-based assay for IPO glucuronidation. Microsomal rates of glucuronidation and P450-dependent NAC/NAL adduct formation were compared in lung, kidney, and liver microsomes from seven species with different target organ toxicities to IPO. Bioactivation rates were highest in pulmonary and renal microsomes from all animal species (except dog) known to be highly susceptible to the extrahepatic toxicities induced by IPO. In a complementary fashion, pulmonary and renal IPO glucuronidation rates were uniformly low in all experimental animals and primates, but hepatic glucuronidation rates were high, as expected. Therefore, with the exception of the dog, the balance between microsomal NAC/NAL adduct and glucuronide formation correlate well with the risk for IPO-induced pulmonary, renal, and hepatic toxicities across species.

Metabolomics of Methylphenidate and Ethylphenidate: Implications in Pharmacological and Toxicological Effects.

Methylphenidate (MPH) is primarily indicated for attention-deficit hyperactivity disorder and narcolepsy therapy. A marked individual variability in the dose-response has been observed, and therefore dosage must be titrated for optimal therapeutic effect with minimal toxicity. This variability has been claimed to be predominantly pharmacokinetic. Moreover, due to its similar pharmacodynamics to amphetamine, MPH has been abused and fatalities have been reported. This review aims to discuss metabolomics of MPH, namely by presenting all major and minor metabolites. Ritalinic acid is the main metabolite. In addition, minor pathways involving aromatic hydroxylation, microsomal oxidation and conjugation have also been reported to form the p-hydroxy-, oxo- and conjugated metabolites, respectively. MPH may undergo transesterification with ethanol producing ethylphenidate, which is also pharmacologically active. It is expected that knowing the metabolomics of MPH may provide further insights regarding individual contribution for MPH pharmacodynamics and toxicological effects, namely if ethanol is co-consumed.

Predicting anxiety responses to halogenated glucocorticoid drugs using the hexobarbital sleep time test

Glucocorticoids (GCs) are used to treat numerous diseases, but their use in limited by adverse side effects. One such effect is occasional increased anxiety. Since the intensity of hepatic microsomal oxidation has been shown to alter responses to GC, we examined the possibility that rats with lower rates of hepatic GC metabolism would have increased anxiety. We hypothesized that the resulting, excessive GC would stimulate brain monoamine oxidase A (MAO-A), which would reduce brain serotonin, and thereby increase anxiety. Hepatic microsomal oxidative intensity was evaluated by the hexobarbital sleep time (HST) test. Results showed that rats with lower rates of hepatic GC metabolism had elevated brain MAO-A activity, reduced brain serotonin, and more anxiety than rats with higher rates of hepatic GC metabolism. We suggest that the HST test, as an integrative test of microsomal oxidation status, should be useful for predicting individual sensitivity to GC and to other drugs metabolized by the hepatic microsomal oxidation system.

Influence of various forms chitosan on microsomal oxidation in the liver and metabolic syndrome

Influence of various forms chitosan on microsomal oxidation in the liver and metabolic syndrome

Influence of various forms chitosan on microsomal oxidation in the liver and metabolic syndrome

Influence of various forms chitosan on microsomal oxidation in the liver and metabolic syndrome

Hepatic biotransformation pathways and ruminal metabolic stability of the novel anthelmintic monepantel in sheep and cattle.

Monepantel (MNP) is a new amino-acetonitrile derivative anthelmintic drug used for the treatment of gastrointestinal (GI) nematodes in sheep. The present work investigated the main enzymatic pathways involved in the hepatic biotransformation of MNP in sheep and cattle. The metabolic stability in ruminal fluid of both the parent drug and its main metabolite (monepantel sulphone, MNPSO2 ) was characterized as well. Additionally, the relative distribution of both anthelmintic molecules between the fluid and particulate phases of the ruminal content was studied. Liver microsomal fractions from six (6) rams and five (5) steers were incubated with a 40μm of MNP. Heat pretreatment (50°C for 2min) of liver microsomes was performed for inactivation of the flavin-monooxygenase (FMO) system. Additionally, MNP was incubated in the presence of 4, 40, and 80μm of methimazole (MTZ), a FMO inhibitor, or equimolar concentrations of piperonyl butoxide (PBx), a well-known general cytochrome P450 (CYP) inhibitor. In both ruminant species, MNPSO2 was the main metabolite detected after MNP incubation with liver microsomes. The conversion rate of MNP into MNPSO2 was fivefold higher (P<0.05) in sheep (0.15±0.08nmol/min·mg) compared to cattle. In sheep, the relative involvement of both FMO and CYP systems (FMO/CYP) was 36/64. Virtually, only the CYP system appeared to be involved in the production of MNPSO2 in cattle liver. Methimazole significantly reduced (41 to 79%) the rate of MNPSO2 production in sheep liver microsomes whereas it did not inhibit MNP oxidation in cattle liver microsomes. On the other hand, PBx inhibited the production of MNPSO2 in liver microsomes of both sheep (58 to 98%, in a dose-dependent manner) and cattle (almost 100%, independently of the PBx concentration added). The incubation of MNP and MNPSO2 with ruminal contents of both species showed a high chemical stability without evident metabolism and/or degradation as well as an extensive degree of adsorption (83% to 90%) to the solid phase of the ruminal content. Overall, these results are a further contribution to the understanding of the metabolic fate of this anthelmintic drug in ruminants.

Duration of hexobarbital-induced sleep and monoamine oxidase activities in rat brain: Focus on the behavioral activity and on the free-radical oxidation.

The present study is focused on the relationship between monoamine oxidase (MAO) activity and hepatic content of cytochrome P450 (CYP), which reflects the status of microsomal oxidation. For vital integrative evaluation of hepatic microsomal oxidation in rats, the hexobarbital sleep test was used, and content of CYP was measured in hepatic microsomes. Rats with short hexobarbital sleep time (SHST) had higher content of microsomal CYP than rats with long hexobarbital sleep time (LHST). Whole brain MAO-A and MAO-B activities, serotonin and carbonylated protein levels were higher in SHST than in LHST rats. MAO-A and MAO-B activities were higher in brain cortex of SHST rats; MAO-A activity was higher only in hypothalamus and medulla of LHST. The same brain regions of LHST rats had higher concentrations of carbonylated proteins and lipid peroxidation products than in SHST rats. MAO activity was correlated with microsomal oxidation phenotype. Rats with higher hepatic content of CYP had higher activities of MAO-A and MAO-B in the brain and higher plasma serotonin levels than rats with lower microsomal oxidation. In conclusion, data obtained in this study showed a correlation between MAO activity and microsomal oxidation phenotype.

ВПЛИВ ТІОТРИАЗОЛІНУ ТА ГЕПАДИФУ НА МЕТАБОЛІЧНІ ПРОЦЕСИ У ТВАРИН З ГОСТРИМ ТОКСИЧНИМ ТА СУБХРОНІЧНИМ УРАЖЕННЯМ АЦЕТАМІНОФЕНОМ НА ФОНІ ДОВГОТРИВАЛОГО ЗАСТОСУВАННЯ ЕСТРОГЕНІВ ТА ПРОГЕСТИНІВ

&lt;p&gt;&lt;strong&gt;INFLUENCE THIOTRIAZOLINE AND HEPADIF ON METABOLIC PROCESSES OF ANIMALS WITH ACUTE TOXIC AND SUBCHRONIC&lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;&lt;strong&gt;LESIONS BY ACETAMINOPHEN WITH PROLONGED USAGE OF ESTROGEN AND PROGESTIN&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;I.B. Ivanusa&lt;/strong&gt;&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p class="Default" align="center"&gt;&lt;em&gt;SHEI “Ternopil State Medical University by I.Ya. Horbachevsky of MPH of Ukraine”&lt;/em&gt;&lt;/p&gt;&lt;p&gt;Ethinylestradiol and levonorgestrel is widely used as oral contraceptives. Acetaminophen has more toxic activity at prolonged their usage, as indicated by our obtained results of endogenous intoxication changing. Significant changes are occurred even at seven-day acetaminophen administration in high therapeutic dose. Usage thiotriazoline and hepadif normalizes investigated parameters of metabolic processes of animals with acute toxic and subchronic lesions by acetaminophen with prolonged usage of estrogen and progestin.&lt;/p&gt;&lt;p&gt; KEY WORDS: acetaminophen, thiotriazoline, hepadif, cytochrome oxidase, succinate dehydrogenase, microsomal oxidation.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Introduction.&lt;/strong&gt; Acetaminophen (paracetamol) is known and frequently used drug as an analgesic and antipyretic. It may be possible poisoning at usage overdoses of paracetamol. The most serious effect of acetaminophen poisoning is liver damage. Thiotriazoline is a synthetic cardio and hepatoprotector. It prevents the damage and destruction of hepatocytes. Hepadif is the most famous combined hepatoprotector. Therapeutic efficacy of Hepadyf is due to physiologically active substances of metabolic action.&lt;br /&gt;Therefore, we set a goal to investigate the effect of acetaminophen on the parameter of energy-saving and microsomal oxidation animals with acute toxic and subchronic lesions by acetaminophen with prolonged usage of estrogen and progestin and the correction by thiotriazoline and hepadif.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;INVESTIGATION METHODS.&lt;/strong&gt; The experiments were performed on white female rats weighing 200 ±20 g, are kept on a standard diet of vivarium and free access to water.&lt;/p&gt;&lt;p&gt;The experimental rats were divided into 4 groups, which (except 1st group) divided into two subgroups: 1st - intact (control); 2&lt;sup&gt;nd&lt;/sup&gt;(a) – poisoning by acetaminophen after 40-day administration of levonorgestrel and ethinylestradiol; 2&lt;sup&gt;nd&lt;/sup&gt;(b) – poisoning by acetaminophen administration within 7 days after 40-day administration of levonorgestrel and ethinylestradiol; 3&lt;sup&gt;rd&lt;/sup&gt;(a) – poisoning by acetaminophen after 40-days administration of levonorgestrel, ethinylestradiol and once Thiotriazoline administration; 3&lt;sup&gt;rd&lt;/sup&gt;(a) – poisoning by acetaminophen administration within 7 days after 40-days administration of levonorgestrel, ethinylestradiol and once Thiotriazoline administration; 4&lt;sup&gt;th&lt;/sup&gt;(a) – poisoning by acetaminophen after 40-days administration of levonorgestrel, ethinylestradiol and Hepadyf administration; 4&lt;sup&gt;th&lt;/sup&gt;(b) – poisoning by acetaminophen administration within 7 days after 40-days administration of levonorgestrel, ethinylestradiol and Hepadyf administration.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;RESULTS AND DISCUSSION.&lt;/strong&gt; Cytochrome oxidase and succinate dehydrogenase activity in rat liver increase compared with affected animals at Thiotriazoline administration. Hepadyf is more effective on the energy-saving processes. Using the drugs for correction had a positive effect on the enzyme activity of microsomal oxidation. In the liver of 3&lt;sup&gt;rd&lt;/sup&gt;(a) group animals N-demethylase activity increased on 29 % compared with poisoning animals, and 3&lt;sup&gt;rd&lt;/sup&gt;(b) group – on 9 %.&lt;/p&gt;&lt;p&gt;Para-hydroxylase activity at action of Thiotriazoline single administration of increased on 92 %, and the seven-time administration – parameter values was as in the control group animals. Positive influence is observed at correction by Hepadyf, but it was slightly less than at correction by Thiotriazoline. In group 4&lt;sup&gt;th&lt;/sup&gt;(a) N- demethylase activity increased on 15 %, 4&lt;sup&gt;th&lt;/sup&gt;(b) - on 4 %. Para-hydroxylase activity changed similarly.&lt;/p&gt;&lt;p&gt;Erythrocytic index of intoxication at Thiotriazoline using in animals with acute poisoning by acetaminophen after 40 days administration of estrogen and progestin decreased in 1.6 times and poisoning by acetaminophen administration within 7 days - 1.7 times and approaching the level of control animals. At Hepadyf using Erythrocytic index also significantly decreased and run up to level of healthy animals in 4&lt;sup&gt;th&lt;/sup&gt;(b) group.&lt;/p&gt;&lt;p class="21"&gt;Parameter of medium weight molecules 1 (MWM&lt;sub&gt;1&lt;/sub&gt;) at Thiotriazoline correction in 3&lt;sup&gt;rd&lt;/sup&gt;(a) group was 45% from level of poisoning animals and approached to parameters in the control animals, in 3&lt;sup&gt;rd&lt;/sup&gt;(b) group did not significantly difference from level in the control group. A similar decrease is observed at definition MWM&lt;sub&gt;2&lt;/sub&gt; – correction by Thiotriazoline normalized of this parameter. "Hepadyf" has the similar effect and to the end of the investigation period parameter was as level of control animals.&lt;/p&gt;&lt;p&gt;Changing of cytosolic enzymes – &lt;a href="https://slovari.yandex.ua/alanine/en-ru"&gt;alanine&lt;/a&gt;- and aspartamine-transferase activity in blood plasma of rats showed negative effect of acetaminophen on the plasma membrane of cells, accompanied by structural changes and increased permeability of membranes. Administrations of corrective drugs regulate the activity of cytoplasmic enzymes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;CONCLUSIONS.&lt;/strong&gt; As illustrated in obtained results, that parameters of oxidative processes and endogenous intoxication normalized at action of corrective drugs. So parameters of endogenous intoxication decreased and partial normalization of energy-saving and microsomal oxidation parameters.&lt;/p&gt;

Hepatobiliary Quiz (Answers)—15 (2015)

Hepatobiliary Quiz (Answers)—15 (2015)

Oxidation of Salicylic Acid and Aspirin by Human Cytochromes P450

Aspirin (acetylsalicylic acid) is a commonly used analgesic. It is rapidly deacetylated both enzymatically and non‐enzymatically to salicylic acid. Salicylic acid can then be further metabolized by conjugation with glycine or glucuronides or by hydroxylation to form 2,3‐dihydroxybenzoic acid (2,3‐DHBA) and 2,5‐dihydroxybenzoic acid (2,5‐DHBA). This oxidation has been suspected to occur from oxygen radicals via Fenton reactions as well as by cytochrome P450 enzymes. We analyzed the formation of 2,3‐DHBA and 2,5‐DHBA in the presence of human liver microsomes by HPLC with fluorescence detection. We were able to determine that microsomal oxidation was much faster for salicylic acid than aspirin. 2,3‐DHBA was found to be the major oxidative product formed from salicylic acid, whereas aspirin could detect only 2,5‐DHBA. Recombinant human P450s 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4 all catalyzed the 5‐hydroxylation of salicylic acid. Inhibitor studies were able to confirm that all six of these enzymes played a role in the formation of 2,3‐ and 2,5‐DHBA, as well as found that 2A6 and 2B6 played a role in the hydroxylation to 2,5‐DHBA. It was also shown in the inhibitor studies that P450 2E1 was the major enzyme contributing to the in both 3‐ and 5‐hydroxylations.This work was supported in part by National Institutes of Health grant R37 CA090426.