• Title/Summary/Keyword: liver metabolism

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Mechanism of action of ferroptosis and its role in liver diseases

  • Dong-Oh Moon
    • Journal of Applied Biological Chemistry
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    • v.66
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    • pp.159-164
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    • 2023
  • Ferroptosis is a type of regulated cell death recently discovered, characterized by the accumulation of iron-dependent lipid peroxides in the cell membrane, and it involves a complex network of signaling pathways, including iron metabolism, lipid peroxidation, and redox regulation. The dysregulation of these pathways can lead to the induction of ferroptosis and the development of liver diseases, such as alcoholic liver disease, non-alcoholic fatty liver disease, viral hepatitis, and liver cancer. Studies have demonstrated that targeting key molecules involved in iron metabolism, lipid peroxidation, and redox regulation can reduce liver injury and improve liver function in different liver diseases by inhibiting ferroptosis. Thus, modulation of ferroptosis presents a promising therapeutic target for treating liver diseases. However, further research is required to gain a more comprehensive understanding of the mechanisms underlying the role of ferroptosis in liver diseases and to develop more effective and targeted treatments.

Serotonin and Energy Metabolism (세로토닌과 에너지 대사)

  • Kyoung-Kon Kim
    • Archives of Obesity and Metabolism
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    • v.3 no.1
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    • pp.35-42
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    • 2024
  • Serotonin, a biogenic amine widely found in many organisms, functions as both a neurotransmitter and hormone. Although serotonin is involved in various physiological processes, this study aimed to review its role in energy metabolism. Given that serotonin cannot cross the blood-brain barrier and is synthesized by two different isoforms of tryptophan hydroxylase in the central nervous system (CNS) and peripheral tissues, it is reasonable to assume that serotonin in the CNS and peripheral tissues functions independently. Recent studies have demonstrated how serotonin influences energy metabolism in metabolic target organs such as the intestines, liver, pancreas, and adipose tissue. In summary, serotonin in the CNS induces satiety and appetite suppression, stimulates thermogenesis, and reduces body weight. Conversely, serotonin in the periphery increases intestinal motility, stimulates gluconeogenesis in the liver, suppresses glucose uptake by hepatocytes, promotes fat uptake by liver cells, stimulates insulin secretion while suppressing glucagon secretion in the pancreatic islets, promotes lipogenesis in white adipose tissue, inhibits lipolysis and browning of white adipose tissue, and suppresses thermogenesis in brown adipose tissue, thereby storing energy and increasing body weight. However, considering that most experimental results were obtained using mice and conducted under specific nutritional conditions, such as high-fat diets, whether serotonin acts in the same way in humans, whether it will act similarly in individuals with normal versus obese weights, and whether its effects vary depending on the type of food consumed, remain unknown.

Metabolism of YH1885 by Rat, Dog, Monkey and Human Liver S9 Fractions

  • Kim, Eun-Joo;Roh, Jung-Koo;Green, Carol
    • Biomolecules & Therapeutics
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    • v.6 no.3
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    • pp.283-288
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    • 1998
  • YH 1885 (5,6-dimethyl -2-(4-fluorophenylamino)-4-(1-methyl -1,2,3,4-tetrahydroisoquinolin -2- yl) pyrimidine hydrochloride) was developed as an antiulcer drug. The objective of this study was to examine a comparative metabolism of YH1885 in rat, dog, monkey and human liver tissues and to determine the metabolite profiles produced by the four species. YH1885 was metabolized by liver 59 fractions from all four species. Control incubations containing 59 fraction but no cofactors, contained essentially no metabolites. Metabolism of YH1885 apparently became saturated in the concentration range studied because the % of YH 1885 metabolized decreased with increasing drug concentration for all four species. Six to nine metabolite peaks were detected in the incubations and the particular profile of metabolites varied with species. The total amount of metabolites formed by liver microsomes from human and monkey were less than microsomes from rat or dog. The major metabolite peak formed by rat liver 597actions fluted near the solvent front on the HPLC or remained at the origin in TLC, indicating that it contained one or more polar metabolites. Dog liver 59 fractions incubations contained four major metabolites that each accounted for about 15 to 20 % of the total radioactivity at the low concentration of YH1885. The metabolite profiles of YH1885 appeared to be similar in incubations with rhesus monkey and human liver 59 fraction. The amount of metabolites formed by rhesus monkey liver preparations was greater than that of human liver that contained prominent metabolite peaks with approximate relative retention time of 0.14 and 0.43.

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Characterization of Deoxypodophyllotoxin Metabolism in Rat Liver Microsomes

  • Lee, Sang-Kyu;Jun, In-Hye;Kang, Mi-Jeong;Jeon, Tae-Won;Kim, Ju-Hyun;Seo, Young-Min;Shin, Sil;Choi, Jae-Ho;Jeong, Hye-Gwang;Lee, Seung-Ho;Jeong, Tae-Cheon
    • Biomolecules & Therapeutics
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    • v.16 no.3
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    • pp.190-196
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    • 2008
  • Deoxypodophyllotoxin (DPT) is a medicinal herb product isolated from Anthriscus sylvestris. DPT possesses beneficial activities in regulating immediate-type allergic reaction and anti-inflammatory activity through the dual inhibition of cyclooxygenase-2 and 5-lipoxygenase. In the present study, the metabolism of DPT was further characterized in rat liver microsomes isolated from male Sprague Dawley rats. The metabolism of DPT was NADPH-dependent. In addition, when liver microsomes were incubated with SKF-525A, a well-known CYP inhibitor, in the presence of $\beta$-NADPH, the metabolism of DPT was significantly inhibited. Using enriched rat liver microsomes, the anticipated isoforms of cytochrome P450s (CYPs) in the metabolism of DPT were partially characterized. Phenobarbital-induced microsomes increased in the formation of metabolite M1. The metabolite M3 was only produced in the enriched microsomes isolated from dexamethasone-treated rats. The results indicated that the metabolism of DPT would be CYP-dependent and that CYP2B and CYP3A might be important in the metabolism of DPT in rats.

Reaction Mechanism of Troleandomycin on the Activity of Human Liver Microsomal Cytochrome P450 3A4 (인체 간 조직의 Cytochrome P450 3A4의 활성에 대한 Troleandomycin의 작용기전)

  • 김복량;오현숙;김혜정
    • Toxicological Research
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    • v.11 no.2
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    • pp.329-335
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    • 1995
  • Incubation of aflatoxin $B_1$ $(AFB_1)$ with microsomes isolated from human liver number 110 yielded two metabolite peaks which were aflatoxin $Q_1$ $(AFQ_1)$ and $(AFB_1)$-exo-8, 9-epoxide (exo-epoxide) in high performance liquid chromatography. Production ratio of $AFQ_1$ to exo-epoxide was 2.43$\pm $0.04. Metabolism of $(AFB_1)$ to $(AFQ_1)$ and exo-epoxide was inhibited by troleandomycin in a same degree although troleandomycin was not activated as a mechanism-based inhibitor. The inhibitory effect was dependent upon either the incubation time with $(AFB_1)$ or the preincubation time before the addition of $(AFB_1)$. Incubation of troleandomycin and NADPH by the microsomes resulted in the formation of a cytochrome P 450 (P450)-metabollc intermediate (MI) complex and the level was approximately 80% of total P450 3A4 in the microsomes. This figure was similar to that of the inhibitory effect of troleandomycin on $AFB_1$ metabolism. Glutathione which was reported that it prevented the formation of MI complex in rat liver microsomes did not inhibit the formation of MI complex in human liver microsomes. These results suggested that the inhibitory effect of troleandomycin on $AFB_1$ metabolism is due to the formation of MI complex with P450 3A4. And the reaction mechanism of troleandomycin by human liver microsomes might be dlfferent from that one by rat liver microsomes.

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Effects of aerobic exercise training on the risk factors for liver diseases in elderly women with obesity and impaired fasting glucose: A pilot study

  • Park, Jae Ho;Kim, Hee-jae;Han, Aleum;Kang, Deuk-mo;Park, Sok
    • Korean Journal of Exercise Nutrition
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    • v.23 no.1
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    • pp.21-27
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    • 2019
  • [Purpose] In the present pilot study, we aimed to investigate the effects of the Silverrobics exercise program, which is similar to aerobic dance, on the factors related to glucose metabolism and liver enzymes. [Methods] Eight elderly women with obesity and impaired fasting glucose participated in the Silverrobics exercise program (60 minutes per session for five times a week for 8 weeks). The program was conducted at 50-60% of the heart rate reserve at 1 to 2 weeks and at 60-80% of the heart rate reserve at 3 to 8 weeks. To verify the effect of this 8-week exercise program on glucose metabolism and liver enzymes, blood analysis at pre- and post-training was performed. [Results] After the Silverrobics exercise program, there were significant decreases in the glucose (p<0.05), glycated hemoglobin A1c (p<0.05), 1,5-anhydroglucitol (p<0.05), and insulin levels (p<0.01) and homeostatic model assessment of insulin resistance score (p<0.05). However, there were no significant effects on the liver enzymes, except for alkaline phosphatase. The alkaline phosphatase level increased after the Silverrobics exercise program (p<0.05). [Conclusion] Although the Silverrobics exercise program had no beneficial effects on the liver enzymes, it may play an important role in preventing liver diseases considering the effects on glucose metabolism.

Effects of Dietary Methionine and Folate Supplementation in Ethanol-Fed Rats

  • Mun, Ju-Ae;Min, Hye-Sun
    • Nutritional Sciences
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    • v.9 no.2
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    • pp.106-111
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    • 2006
  • Chronic alcohol consumption is associated with perturbation of hepatic metabolism of sulphur-containing amino acid. The goal of present study was to evaluate the influence of dietary supplementation of methionine or folate to chronically ethanol-fed mts on the metabolism of sulfur-containing amino acids and one-carbon metabolism. Sprague-Dawley male mts were fed Lieber-Decarli liquid diet with 0% ethanol (control), 36% ethanol (E), 36% ethanol combined with methionine supplement (EM) or folate supplement (EF) for 8 weeks. Hepatic S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), plasma folate and homocysteine (Hcy), urinary excretion of folate and formiminoglutamate were investigated after feeding experimental diets. Growth was retarded by 36% ethanol consupmtion (E, EM and EF) (p<0.01). Liver total fat (p<0.05) and plasma ALT (P<0.01) were increased by methionine supplementation (EM), implicating fatty liver and liver injury. Liver folate was increased slightly by folate supplementation (EF) (p=0.077). Urinary folate loss was increased 2.3 fold by ethanol consumption (E) and 17.2 fold by folate supplementation (EF), while decreased by methionine supplementation (EM) (p<0.000l). Plasma Hcy was increased 1.9 fold by methionine supplementation (EM) in ethanol-fed mts (p<0.05), which was related with decreased methionine synthase activity (p<0.05). Hepatic SAM/SAH ratio was depressed by methionine supplementation in ethanol-fed mts (EM) (p<0.05). Urinary formininoglutamate (Figlu) excretion after histidine loading was increased by ethanol ingestion and reduced by methionine supplementation (p<0.00l). Based on these data, methionine supplementation appears to accelerate histidine oxidation. In conclusion, dietary supplementation of methionine to ethanol-fed mts exacerbates alcoholic liver injury possibly by complicating sulphur-containing amino acid metabolism, as while it may have beneficial effects on folate and histidine metabolism.

Effects of Gastrodiae rhizoma on the Liver Function and Alcohol Metabolism in Alcohol Treated Rats (천마 추출물이 알코올을 투여한 흰쥐의 간 기능 및 알코올 대사에 미치는 영향)

  • Park, Soon-Ja;Kang, Ju-Hyeon;Kong, Hyun-Joo;Hwang, Su-Jung;Jang, Jung-Hyeon;Yang, Kyung-Mi
    • Korean journal of food and cookery science
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    • v.32 no.6
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    • pp.818-827
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    • 2016
  • Purpose: This study was conducted to investigate the effect of freeze-dried Gastrodiae rhizoma powder (GR) on the liver function and alcohol metabolism in alcohol treated rats. Methods: The rats were administered various concentrations of GR (100 mg, 200 mg, 300 mg/kg B.W.) for 3 days 1 hour before 50% (v/v) ethanol (3 g/kg B.W.) administration. Two tests focusing on liver function and alcohol metabolism in acute alcohol treatment were carried out. Results: Glutamic oxaloacetic transaminase activity was significantly increased by alcohol treatment, and was decreased by 100 mg GR administration. Acute ethanol treatment led to significant increase in alcohol and acetaldehyde levels of serum and liver. However, 100 mg GR administration led to a significant reduction in increased alcohol level in the serum with decreased alcohol dehydrogenase (ADH) activity and increased acetaldehyde level in liver was significantly reduced by three levels. Conclusion: These results suggest that GR can be effective in enhancing liver function and alcohol metabolism in the alcohol-treated rats. Studies on the appropriate dosage of GR should further be developed to treat alcohol detoxification and stimulate liver function.