Metabolism In Rat Liver Research Articles

Chronic Alcohol Exposure Differentially Alters One-Carbon Metabolism in Rat Liver and Brain.

Epigenetic mechanisms such as DNA methylation play an important role in regulating the pathophysiology of alcoholism. Chronic alcohol exposure leads to behavioral changes as well as decreased expression of genes associated with synaptic plasticity. In the liver, it has been documented that chronic alcohol exposure impairs methionine synthase (Ms) activity leading to a decrease in S-adenosyl methionine/S-adenosyl homocysteine (SAM/SAH) ratio which results in DNA hypomethylation; however, it is not known whether similar alterations of SAM and SAH levels are also produced in brain. Male adult Sprague Dawley rats were fed chronically with Lieber-DeCarli ethanol (EtOH) (9% v/v) or control diet. The EtOH-diet-fed rats were withdrawn for 0 and 24hours. The cerebellum and liver tissues were dissected and used to investigate changes in one-carbon metabolism, SAM, and SAH levels. We found that chronic EtOH exposure decreased SAM levels, SAM/SAH ratio, Ms, methylene tetrahydrofolate reductase, and betaine homocysteine methyltransferase (Bhmt) expression and increased methionine adenosyltransferase-2b (Mat2b) but not Mat2a expression in the liver. In contrast, chronic EtOH exposure decreased SAH levels, increased SAM/SAH ratio and the expression of Mat2a and S-adenosyl homocysteine hydrolase, while the levels of SAM or Bhmt expression in cerebellum remained unaltered. However, in both liver and cerebellum, chronic EtOH exposure decreased the expression of Ms and increased Mat2b expression. All chronic EtOH-induced changes of one-carbon metabolism in cerebellum, but not liver, returned to near-normal levels during EtOH withdrawal. These results indicate a decreased "methylation index" in liver and an increased "methylation index" in cerebellum. The opposing changes of the "methylation index" suggest altered DNA methylation in liver and cerebellum, thus implicating one-carbon metabolism in the pathophysiology of alcoholism.

Effects of cyclic fatty acids on rat liver and plasma fatty acid metabolism and inflammation mediators depend on dietary lipids

ObjectiveThis study aimed to determine the interactions between dietary fatty acids and cyclic fatty acid monomers (CFAM) on liver and plasma lipids and inflammationMethodsTwo oils (canola oil and soybean oil) were used in the experiment while 0.5% of CFAM were added to the CFAM diets, thus generating four diet groups: canola oil (CO), soybean oil (SO), canola oil and CFAM (CC), and soybean oil and CFAM (SC). 36 male Wistar rats (n=9) were fed those diets for 28 days, liver and plasma lipids were analyzed by gas‐liquid chromatography and inflammation markers were analyzed enzymatic methods.ResultsAlthough CFAM alone induced an accumulation of TAG, liver fatty acid analysis showed that rats fed the CC diet had less stearic acid (STA), arachidonic acid (ARA), and docosahexaenoic acid (DHA) but more oleic acid (OLA) and total MUFA than those fed the CO, SO and SC diets. However, no difference was observed between rats fed SO and SC diets. Significant interactions between the type of oil and CFAM were also observed in plasma fatty acids for the following fatty acids: palmitic acid (PAM, P = 0.039), linoleic acid (AL, P = 0.023), docosapentaenoic acid (DPAn‐3 P<0.0001), and total PUFAn‐3 (P = 0.028). In particular, it was observed that CC‐fed rats had less AL than the SC (P<0.0001). CFAM induced lower ALT levels (P<0.0001), lower ALT/AST ratio (P = 0.003), and higher plasma total cholesterol levels (P = 0.024) compared with the non‐CFAM diets. There were interactions between oil and CFAM for plasma AST (P = 0.04), AST/ALT ratio (P = 0.02), and IL‐6 (P = 0.02).ConclusionsWhile showing that CFAM effects on lipid metabolism are exacerbated when used with a high‐oleic acid oil, these results suggest that CFAM effects are altered by dietary lipids. These results reinforce the need for a selected use of vegetable oils in domestic and industrial settings. Other associations of CFAM with oils of different ratios MUFA/PUFA, PUFAn‐6/n‐3, PUFA/SFA can be used to further assess the interactions between CFAM and dietary fats.Support or Funding InformationCanadian Natural Sciences and Engineering Research Council

Exposition of Uranium Modulates of the Expression of Cyps and Transporters Involved in Cholesterol Metabolism in Rat Liver

Exposition of Uranium Modulates of the Expression of Cyps and Transporters Involved in Cholesterol Metabolism in Rat Liver

Vitamin E and caloric restriction promote hepatic homeostasis through expression of connexin 26, N-cad, E-cad and cholesterol metabolism genes

Connexins (Cx) and cadherins are responsible for cell homeostasis. The Cx activity is directly related to cholesterol. The present work investigates whether vitamin E, with or without caloric restriction (CR), alters the mRNA expression of Cx26, Cx32, Cx43, N-cadherins (N-cads), E-cadherins (E-cads) and alpha-smooth muscle actin (α-SMA), and evaluates their relation to cholesterol metabolism in rat liver. Animals were divided into different groups: control with ad libitum diet (C), control+vitamin E (CV), aloric restriction with intake to 60% of group C (CR), and the intake of group CR+vitamin E (RV). There were increases of manganese superoxide dismutase (Mn-SOD) and glutathione S-transferase mu 1, indicating antioxidant effects of CR and vitamin E. An increase of nitric oxide in the CR group was in agreement with the Mn-SOD data. Supplementation with vitamin E, with or without CR, upregulated the expression of Cx26 mRNA and increased low-density lipoprotein cholesterol (LDL-c) in the CV group. Reductions of Cx32 and Cx43 were associated with lower LDL-c. Increases in Hmgcr and low-density lipoprotein receptor (LDLr) in the CV and RV groups could be explained by the effect of vitamin E. A reduction of LDLr in the CR group was due to the reduced dietary intake. Increases in cadherins in the CV, CR and RV groups were indicative of tissue maintenance, which was also supported by increases of α-SMA in groups CV and RV. Finally, vitamin E, with or without CR, increased Cx26, probably modulated by expression of the Hmgcr and LDLr genes. This suggests important relationship of Cxs and cholesterol metabolism genes.

Application of spectroscopy (1HMRS) to assess liver metabolite concentrations in rats with intrauterine growth restriction

Objective: Proton magnetic resonance spectroscopy (1H-MRS) measurement of liver metabolism in intrauterine growth restriction rats has seldom been reported. This study investigated the application of 1H-MRS in assessing liver metabolism in newborn pups that experienced intrauterine growth restriction.Methods: Intra-uterine growth restriction was established by feeding rats low-protein diets during pregnancy. Newborn pups received conventional magnetic resonance imaging and 1H-MRS using a 3.0T whole body MR scanner at 3, 8 and 12 weeks post birth.Results: The success rate of 1H-MRS was 83.33%. Significantly lower body weight, BMI and body length at 3 weeks as well as significantly lower body weight, BMI and waist circumference at 8 and 12 weeks were observed in newborn pups of IUGR rats compared with pups of control rats. Significant differences in ACho/H2O, ACr/H2O, AGlx/H2O and ALipid/H2O at 3 and 8 weeks as well as significant differences in ACr/H2O, ALipid/H2O and AGlx/H2O at 12 weeks were observed between pups of control rats and pups of IUGR rats.Conclusion: 1H-MRS allows noninvasive assessment of liver metabolism in the rat and demonstrated the poor liver development of rats that experienced IUGR.

Poor and enantioselective bioavailability of naftopidil enantiomers is due to extensive and stereoselective metabolism in rat liver

Racemic naftopidil (NAF) is used to treat benign prostatic hyperplasia (BPH) and prostatic cancer (PCa). It exhibits greater efficacy but requires higher dose than other ɑ1-adrenoceptor blockers because of its poor bioavailability. It was previously shown that bioavailability of S(−)-NAF (14.5%) was twice that of R(+)-NAF (6.8%). The present study aimed to elucidate the major factors contributing to the poor and enantioselective bioavailability of NAF. First, absorption of NAF enantiomers was examined using a perfusated intestinal model. NAF enantiomers were found to be equally and highly permeable in all segments of the intestine. Second, the metabolites formed in different parts of the intestine and in bile were investigated. Glucuronidation of NAF enantiomers was found to occur primarily in the liver. Third, a new method consisting of ultra performance liquid chromatography coupled with triple-quadruple mass spectrometry (UPLC–MS/MS) was employed to quantify and calculate the pharmacokinetic parameters of NAF enantiomers and their glucuronides after the enantiomers were intravenously injected into rats. The amounts of R(+)-NAF glucuronide (R(+)-NAF-G) and S(−)-NAF glucuronide (S(−)-NAF-G) were six-fold higher than that of R(+)-NAF, and three-fold higher than that of S(−)-NAF. Glucuronidation of S(−)-NAF was faster than that of R(+)-NAF, but the conjugated amount was half of that of R(+)-NAF. Thus, bioavailability of S(−)-NAF was twice that of R(+)-NAF. In conclusion, extensive phase II metabolism in the liver significantly contributes to the low bioavailability of NAF enantiomers. Glucuronidation is the most important metabolic pathway for NAF enantiomers. Glucuronidation of S(−)-NAF is faster but occurs to a lesser extent than that of R(+)-NAF.

Effects ofIlex paraguariensis(yerba mate) on the hypothalamic signalling of insulin and leptin and liver dysfunction in adult rats overfed during lactation

Ilex paraguariensis (yerba mate) has a beneficial effect in the management of obesity. Here, we studied the effects of yerba mate on hypothalamic changes in leptin and insulin signalling, oxidative stress and liver morphology and metabolism in postnatal early overfeeding (EO) Wistar rats. To induce EO, the litter size was reduced to three pups per dam, and litters with 10 pups per dam were used as a control (10 litters each). On postnatal day (PN) 150, EO offspring were subdivided into EO and EO+mate groups (10 animals each), which were treated with water or mate tea [1 g/kg body weight (BW)/day, by gavage], respectively, for 30 days. The C offspring received water. On PN180, yerba mate treatment prevented BW gain and reduced total body fat, visceral fat and food intake in comparison with the EO group. Leptin and insulin signalling in the hypothalamus measured by Western blotting was reduced only in the EO group. Yerba mate treatment had a greater impact on insulin signalling normalization. In the liver, yerba mate treatment normalized antioxidant enzyme activities and, consequently, decreased lipid peroxidation, determined by malondialdehyde content. In addition, the steatosis level and the liver triglyceride content were also restored. Thus, for the first time, yerba mate was demonstrated to increase antioxidant defences and improve liver metabolism in adult rats that were overfed during lactation, possibly through improvements in the hypothalamic action of insulin. These findings may be important for the treatment of obesity-related disorders.

Biomechanism of chlorogenic acid complex mediated plasma free fatty acid metabolism in rat liver.

BackgroundPlasma free fatty acids (FFA) are involved in blood lipid metabolism as well as many health complications. The present study was conducted to evaluate the potential role of chlorogenic acid complex from green coffee bean (CGA7) on FFA metabolism in high fat diet fed rats.MethodsHyperlipidemia was induced in Wistar rats using high-fat diet. The animals were given CGA7/orlistat concurrently for 42 days. The parameters analysed during the study include plasma and liver total cholesterol (TC), Triglycerides (TG) and FFA. AMPK activation in the liver was analysed through ELISA. The multiple factors involved in AMPK mediated FFA metabolism were analysed using western blotting.ResultsCGA7 (50, 100, 150 mg/kg BW) decreased triglycerides (TG) and FFA levels in plasma and liver. CGA7 administration led to the activation of AMP-activated protein kinase (AMPK) and a subsequent increase in the levels of carnitine palmitoyltransferase 1 (CPT-1). There was a decrease in acetyl-CoA carboxylase (ACC) activity as evident by the increase in its phosphorylation level.ConclusionChlorogenic acids improved the blood lipid metabolism in rats by alleviating the levels of FFA and TG, modulating the multiple factors in liver through AMPK pathway. The study concludes that CGA7 complex can be promoted as an active ingredient in nutrition for obesity management.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1258-y) contains supplementary material, which is available to authorized users.

Microarray Analysis of Mitochondrial Metabolism in Rat Liver and Skeletal Muscle during Perinatal Period: Striking Changes with Emphasis on Coenzyme Q Biosynthesis

Microarray Analysis of Mitochondrial Metabolism in Rat Liver and Skeletal Muscle during Perinatal Period: Striking Changes with Emphasis on Coenzyme Q Biosynthesis

Multiband spectral-spatial RF excitation for hyperpolarized [2-13 C]dihydroxyacetone 13 C-MR metabolism studies.

To develop a specialized multislice, single-acquisition approach to detect the metabolites of hyperpolarized (HP) [2-13 C]dihydroxyacetone (DHAc) to probe gluconeogenesis in vivo, which have a broad 144 ppm spectral range (∼4.6 kHz at 3T). A novel multiband radio-frequency (RF) excitation pulse was designed for independent flip angle control over five to six spectral-spatial (SPSP) excitation bands, each corrected for chemical shift misregistration effects. Specialized multiband SPSP RF pulses were designed, tested, and applied to investigate HP [2-13 C]DHAc metabolism in kidney and liver of fasted rats with dynamic 13 C-MR spectroscopy and an optimal flip angle scheme. For comparison, experiments were also performed with narrow-band slice-selective RF pulses and a sequential change of the frequency offset to cover the five frequency bands of interest. The SPSP pulses provided a controllable spectral profile free of baseline distortion with improved signal to noise of the metabolite peaks, allowing for quantification of the metabolic products. We observed organ-specific differences in DHAc metabolism. There was two to five times more [2-13 C]phosphoenolpyruvate and about 19 times more [2-13 C]glycerol 3-phosphate in the liver than in the kidney. A multiband SPSP RF pulse covering a spectral range over 144 ppm enabled in vivo characterization of HP [2-13 C]DHAc metabolism in rat liver and kidney. Magn Reson Med 77:1419-1428, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

The Disposition of Oxymatrine in the Vascularly Perfused Rat Intestine-Liver Preparation and Its Metabolism in Rat Liver Microsomes

The study was aimed to investigate the absorption and metabolism of oxymatrine (OMT) which contributed to its poor bioavailability. Determinations of OMT absorption and metabolism in rats were evaluated using techniques of the in situ perfused rat intestine-liver preparation and recirculated intestine preparation. Furthermore, chemical inhibition experiments in rat liver microsomes were used to determine the principal cytochrome P450 (CYP) isoforms involved in OMT metabolism. In the intestine-liver preparation, the steady state liver extraction ratio (0.753 ± 0.054) of OMT was 33 times higher than that for the intestine (0.023 ± 0.002). The portal vein mainly consisted of OMT, and was devoid of the metabolite matrine, whereas both OMT and matrine were detected in hepatic vein. With the intestine preparation, the extent of OMT absorption at the end of 120 min of perfusion was 4.79 ± 0.352%. The first-order rate constant for OMT absorption was 0.05 ± 0.003 min−1. The inhibitor of CYP3A2 had strong inhibitory effect on OMT metabolism in a concentration-dependent manner, and value was reduced to 29.73% of control. The 2 perfusion techniques indicated that poor bioavailability of OMT in rats is due mostly to poor absorption and higher hepatic elimination and CYP3A2 appears to contribute to OMT metabolism in rat liver.

Tryptophan Metabolism in Rat Liver after Administration of Tryptophan, Kynurenine Metabolites, and Kynureninase Inhibitors

Rat liver tryptophan (Trp), kynurenine pathway metabolites, and enzymes deduced from product/substrate ratios were assessed following acute and/or chronic administration of kynurenic acid (KA), 3-hydroxykynurenine (3-HK), 3-hydroxyanthranilic acid (3-HAA), Trp, and the kynureni-nase inhibitors benserazide (BSZ) and carbidopa (CBD). KA activated Trp 2,3-dioxygenase (TDO), possibly by increasing liver 3-HAA, but inhibited kynurenine aminotransferase (KAT) and kynureninase activities with 3-HK as substrate. 3-HK inhibited kynureninase activity from 3-HK. 3-HAA stimulated TDO, but inhibited kynureninase activity from K and 3-HK. Trp (50 mg/kg) increased kynurenine metabolite concentrations and KAT from K, and exerted a temporary stimulation of TDO. The kynureninase inhibitors BSZ and CBD also inhibited KAT, but stimulated TDO. BSZ abolished or strongly inhibited the Trp-induced increases in liver Trp and kynurenine metabolites. The potential effects of these changes in conditions of immune activation, schizophrenia, and other disease states are discussed.

Oral administration of Nigella sativa oil ameliorates the effect of cisplatin on membrane enzymes, carbohydrate metabolism and oxidative damage in rat liver.

Cisplatin (CP) is a potent anti-cancer drug widely used against solid tumors. However, it exhibits pronounced adverse effects including hepatotoxicity. Several strategies were attempted to prevent CP hepatotoxicity but were not found suitable for therapeutic application. Nigella sativa has been shown to prevent/reduce the progression of certain type of cardiovascular, kidney and liver diseases. Present study investigates whether N. sativa oil (NSO) can prevent CP induced hepatotoxic effects. Rats were divided into four groups viz. control, CP, NSO and CPNSO. Animals in CPNSO and NSO group were administered NSO (2ml/kg bwt, orally) with or without single hepatotoxic dose of CP (6mg/kgbwt, i.p.) respectively. CP hepatotoxicity was recorded by increased serum ALT and AST activities. CP treatment caused oxidant/antioxidant imbalances as reflected by increased lipid peroxidation and decreased enzymatic and non-enzymatic antioxidants. Furthermore, the activities of various carbohydrate metabolism and membrane enzymes were altered by CP treatment. In contrast, NSO administration to CP treated rats, markedly ameliorated the CP elicited deleterious alterations in liver. Histopathological observations showed extensive liver damage in CP treated animals while greatly reduced tissue injury in CPNSO group. In conclusion, NSO appears to protect CP induced hepatotoxicity by improving energy metabolism and strengthening antioxidant defense mechanism.

Curcumin protects against gallic acid-induced oxidative stress, suppression of glutathione antioxidant defenses, hepatic and renal damage in rats

Curcumin (Cur) and gallic acid (Gal) are major food additives. Cur has well-known antioxidant properties, whereas Gal has both antioxidant and pro-oxidant effects. The present study investigated the effects of oral administration of Gal with or without Cur on antioxidant enzymes activities, glutathione (GSH) and the enzymes in its metabolism in rat liver in vivo and markers of tissue damage in the serum. Results showed that the increase in serum creatinine level, alkaline phosphatase and lactate dehydrogenase activities by Gal treatment were inhibited by combined administration of Gal and Cur. The decrease in GSH-peroxidase, GSH-S-transferase, superoxide dismutase and GSH-reductase activities by Gal treatment were inhibited when both Gal and Cur were administered together. The malondialdehyde concentration and catalase activity were significantly increased following administration of Gal but not when the administration of Gal was combined with Cur. Finally, the increase in GSH level was seen following administration of Cur alone or in combination with Gal but not with Gal alone. These results suggest that Gal might induce oxidative stress in the rat liver and affect renal function that can be inhibited by the combined administration of Gal and Cur.

Study on hepatotoxicity of aqueous extracts of Polygonum multiflorum in rats after 28-day oral administration: cholestasis-related mechanism

To study the effect of aqueous extracts of Polygonum multiflorum (AEPM) on bile acid synthesis, metabolism and transfer-related molecules in rat liver and the hepatotoxicity-related mechanism of P. multiflorum. Sprague-Dawley rats were orally administered with 30, 60 g x kg(-1) APEM once everyday for consecutively 28 days. At the end of the experiment, mRNA and protein expressions of hepatic MRP3, MRP2, BSEP, FXR and CYP7A1 were detected by Real-time PCR and Western blot Compared with the normal group, the AEPM high dose group showed significant increases in mRNA expressions of hepatic MRP3 and BSEP of male rats (P < 0.05); AEPM high and low dose groups revealed a notable decrease in mRNA expressions of hepatic FXR (P < 0.05) and remarkable rises in mRNA expressions of hepatic MRP3, MRP2, BSEP, CYP7A1 among female rats (P < 0.05). According to the test results of western blot assay, AEPM high and low dose groups showed consistent changes in protein and mRNA expressions hepatic MRP3, MRP2, BSEP, FXR, CYP7A1. The 28 oral administration with AEPM in rats showed a certain effect on expressions of bile acid synthesis, metabolism and transfer-related proteins, as well as cholestatic or choleretic effects in the mRNA expression.

Influence of cancer cachexia on drug liver metabolism and renal elimination in rats.

BackgroundBody wasting and cachexia change body composition and organ function, with effects on drug pharmacokinetics. The aim of this study was to investigate how cancer and cancer cachexia modify liver metabolism and renal drug elimination in rats.MethodsNine male Wistar-Han rats received a single oral dose of midazolam and propranolol (markers of hepatic metabolism), and 10 rats received single intravenous dose of iohexol, a marker of glomerular filtration rate. After drug delivery, multiple dried blood samples were obtained within 2 h post-dose to evaluate drug pharmacokinetic profiles. After baseline sampling (D0), rats were injected with tumour cells. Drug application and blood sampling were repeated when rats developed tumours (Day 5—D5), and when rats were severely cachectic (Day 10—D10). Clearance (CL) and volume of distribution (Vd) of drugs were assessed with non-linear mixed effects modelling. Weight and body composition were measured on D0 and D10 and were related to pharmacokinetic parameters.ResultsAll three drugs showed non-significant trend towards increased CL and Vd on D5. On D10, midazolam and propranolol CL and midazolam Vd significantly decreased from baseline (−80.5%, −79.8%, and −72.0%, respectively, P < 0.05 for all). Iohexol CL decreased by 29.8% from baseline value on D10, which was related to body weight loss (Pearson's r = 0.837, P = 0.019).ConclusionsHepatic metabolism and renal drug elimination are significantly reduced in cachexia, which could increase risk of dose-related adverse events.

Impact of fasting time on hepatic lipid metabolism in nutritional animal studies.

Many animal studies on improvement of lipid metabolism, using dietary components, fast the animals on the final day of the feeding. Although fasting has a significant impact on lipid metabolism, its time-dependent influence is not fully understood. We examined the effects of several fasting times on lipid metabolism. Rats fed with a semisynthetic diet for 2 wk were killed after 0 (9:00 am), 6 (7:00 am-1:00 pm), 9 (0:00 am-9:00 am), and 13 h (8:00 pm-9:00 am) of fasting. Compared to the 0 h group, marked reduction of liver weight and hepatic triacylglycerol content was observed in the 9 and 13 h groups. Activities of hepatic enzymes involved in fatty acid synthesis gradually decreased during fasting. In contrast, drastic time-dependent reduction of gene expression, of the enzymes, was observed. Expression of carnitine palmitoyltransferase mRNA was higher in the fasting groups than in the 0 h group. Our study showed that fasting has a significant impact on several parameters related to lipid metabolism in rat liver.

Effect of dietary α-lipoic acid on the mRNA expression of genes involved in drug metabolism and antioxidation system in rat liver.

In the present study, the mRNA levels of hepatic proteins involved in the drug metabolism of rats fed α-lipoic acid were evaluated by DNA microarray and real-time PCR analyses. Experimental diets containing 0, 0·1, 0·25 and 0·5 % (w/w) α-lipoic acid were fed to four groups of rats consisting of seven animals each for 21 d. DNA microarray analysis revealed that the diet containing 0·5 % α-lipoic acid significantly (P< 0·05) increased the mRNA levels of various phase I drug-metabolising enzymes up to 15-fold and phase II enzymes up to 52-fold in an isoenzyme-specific manner. α-Lipoic acid also up-regulated the mRNA levels of some members of the ATP-binding cassette transporter superfamily, presumed to be involved in the exportation of xenobiotics, up to 6·6-fold. In addition, we observed that α-lipoic acid increased the mRNA levels of many proteins involved in antioxidation, such as members of the thiol redox system (up to 5·5-fold), metallothioneins (up to 12-fold) and haeme oxygenase 1 (1·5-fold). These results were confirmed using real-time PCR analysis, and α-lipoic acid dose dependently increased the mRNA levels of various proteins involved in drug metabolism and antioxidation. Consistent with these observations, α-lipoic acid dose dependently increased the hepatic concentration of glutathione and the activities of glutathione reductase and glutathione transferase measured using 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrates, but decreased the hepatic and serum concentrations of malondialdehyde. In conclusion, the present study unequivocally demonstrated that α-lipoic acid increases the mRNA expression of proteins involved in drug metabolism and antioxidation in the liver.

Compartmentation of azelate and glutarate metabolism in rat liver (982.5)

Azelate (C9) and glutarate (C5) are odd‐chain dicarboxylates. Azelate, derived from the oxidation of oleate, is an inhibitor of tyrosinase and thioredoxin reductase. The compartmentation of azelate metabolism and its final metabolic fates are not known. We investigated the metabolism of azelate in rat liver using a combination of metabolomics and mass isotopomer analysis. Isolated rat livers were perfused with 2 mM (un)labeled azelate or glutarate ([13C9]azelate or [13C5]glutarate) for 2 h in recirculating mode. Perfusate and liver were analyzed by GC‐MS and LC‐MS/MS. The data showed that: (i) azelate oxidation starts in peroxisomes, and ends in mitochondria; (ii) glutarate oxidation occurs only in mitochondria; (iii) azelate forms pimeloyl‐CoA and glutaryl‐CoA, but not malonyl‐CoA, (iv) an unknown reaction removes one carbon from azelaoyl‐CoA forming octanedioyl‐CoA, then hexanedioyl‐CoA, (v) the metabolism of glutarate to acetyl‐CoA via 3‐hydroxyglutaryl‐CoA, crotonyl‐CoA and S‐3‐hydroxybutyryl‐CoA is confirmed.Grant Funding Source: NIH R33DK07029 and Cleveland Mt. Sinai Health Care Foundation

Effect of the prolonged high-fat diet on the fatty acid metabolism in rat blood and liver.

BackgroundContradictory data on consequences of prolonged high-fat diet requires a detailed study of the influence of nutritional high-fat load mechanisms on the peculiarity of lipid metabolism in blood and liver. The present study was undertaken to investigate the fatty acid composition of polar and neutral lipids of the blood plasma, erythrocytes and liver in Wistar rats under the conditions of a prolonged high-fat diet.MethodsThe study was conducted on 60 adult white male Wistar rats. The animals were fed on a high-fat diet consisted of the beef fat and cholesterol (19% and 2% of the total diet, respectively) up to 180 days. The fatty acid composition of the polar and neutral lipids of plasma, erythrocytes and liver were analyzed by the gas chromatography. Statistical data processing was performed by the methods of descriptive statistics with Statistica 6.0.ResultsThe prolonged unbalanced diet rich in cholesterol and saturated fatty acids resulted in compensatory biosynthesis of the fatty acids in the rat’s liver, the inhibition of synthesis of apoproteins and lipoproteins, disruption of the active transport of fatty acids to tissue cells. This launched the accumulation of 20:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3 in the liver and blood plasma and deficiency of 18:2n-6, 20:5n-3 and 22:6n-3 in the erythrocytes.ConclusionsAdaptive adjustment of lipid metabolism un0064er conditions of the high-fat diet induced inhibition of the formation of lipoproteins (VLDL cholesterol) in the liver, compensatory synthesis of 18:1n-9, 20:5n-3, and 20:3n-6 with primary esterification of PUFA n-3 series to neutral lipids.