• Molecules and Cells
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• v.41 no.10
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• pp.900-908
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• 2018

Insulin resistance is closely associated with metabolic diseases such as type 2 diabetes, dyslipidemia, hypertension and atherosclerosis. Thiazolidinediones (TZDs) have been developed to ameliorate insulin resistance by activation of peroxisome proliferator-activated receptor (PPAR) ${\gamma}$. Although TZDs are synthetic ligands for $PPAR{\gamma}$, metabolic outcomes of each TZD are different. Moreover, there are lack of head-to-head comparative studies among TZDs in the aspect of metabolic outcomes. In this study, we analyzed the effects of three TZDs, including lobeglitazone (Lobe), rosiglitazone (Rosi), and pioglitazone (Pio) on metabolic and thermogenic regulation. In adipocytes, Lobe more potently stimulated adipogenesis and insulin-dependent glucose uptake than Rosi and Pio. In the presence of pro-inflammatory stimuli, Lobe efficiently suppressed expressions of pro-inflammatory genes in macrophages and adipocytes. In obese and diabetic db/db mice, Lobe effectively promoted insulin-stimulated glucose uptake and suppressed pro-inflammatory responses in epididymal white adipose tissue (EAT), leading to improve glucose intolerance. Compared to other two TZDs, Lobe enhanced beige adipocyte formation and thermogenic gene expression in inguinal white adipose tissue (IAT) of lean mice, which would be attributable to cold-induced thermogenesis. Collectively, these comparison data suggest that Lobe could relieve insulin resistance and enhance thermogenesis at low-concentration conditions where Rosi and Pio are less effective.

• Toxicological Research
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• v.18 no.3
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• pp.293-300
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• 2002

Chemical carcinogen-induced alteration of aldehyde metabolic enzymes were examined in clone 9 cell. Diethylnitrosamine (DENA), N-nitrosoethylurea (NEU) and N-nitrosomorpholine (NNM) were wed as model carcinogens. Changes in enzyme activities by repetitive treatment of DENA, NEU or NNM were analyzed in terms of specific activities and activity stainings of the enzymes on the gel. Upon treatment of DENA, lipid peroxide level increased upto 10 fold, indicating strong oxidative stress state of the cell. Notable enhancement of ADH and ALDH activity occurred after DENA treatment, while glutathione-S-transferase activity was slightly increased. Furthermore, about 2.5 fold higher superoxide dismutase (SOD) activity was detected during deactivation of catalase (CAT) activity by repetitive treatment of DENA. However in NEU-treated cell, about 2.3 fold higher ALDH activity was found while ADH activity was slightly increased. Notable increase CAT and SOD could also be found. In contrast, maximum 3.5 fold higher CAT activity occurred during SOD deactivation in NNM-treated cell. These results suggest that there might be different enzymatic responses in relation to cell protection against DENA, NEU or NNM.

• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.8-18
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• 2002

Early and accurate diagnosis of tumors using positron omission tomography (PET) has been the focus of considerable interest due to its high metastasis and mortality rates at late detection. PET radiopharmaceuticals-which exhibit a high tumor-to-background uptake ratio, and appropriate metabolic characteristics, and pharmacokinetics-are attractive tools for tumor imaging. Tumor imaging by these radiopharmaceuticals are based on metabolic and receptor imaging. The former is based on accelerated metabolism in tumor tissue compared to normal tissue and the rate roughly corresponding to the rate of growth of tumors. Radiopharmaceuticals for this purpose include radiolabeled sugars, amino acids, and nucleosides which detect increased glucose utilization, protein synthesis, and DNA synthesis, respectively. Tumor receptor imaging is based on the proliferation of tumor cells regulated by many hormones and growth factors, which bind to the corresponding receptors and exhibit the biological responses Radiopharmaceuticals used to image the tumor receptor systems may be ligands for the specific receptors and antibodies for the growth factor receptors. Some antitumor agents have been labeled with radionuclides and used to study in vivo biodistribution and pharmacokinetics in humans. This overview describes typical PET radiopharmaceuticals used for tumor imaging based on their uptake mechanisms.

• Asian Journal of Atmospheric Environment
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• v.9 no.3
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• pp.214-221
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• 2015

This study considers mean skin temperature to calculate expected temperature using the new heat balance model because the skin temperature is the most important element affecting the heat balance outdoors. For this, we measured the skin temperature in high temperature condition of Korea and applied it to calculate the expected temperature. The calculated expected temperature is compared with the result calculated using previous models which use the estimated mean skin temperature by considering metabolic rate only. Results show that the expected temperatures are higher when measured mean skin temperature is applied to the model, compared to the expected temperature calculated by applying mean skin temperature data calculated using metabolic rate like previous models. The observed mean skin temperature was more suitable for outside conditions and expected temperature is underestimated when mean skin temperature calculated by the equation using metabolic rate is used. The model proposed in this study has a few limitations yet, but it can be applied in various ways to facilitate practical responses to extreme heat.

• Analytical Science and Technology
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• v.35 no.4
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• pp.181-188
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• 2022

This paper describes a comparative analysis of yeast cell viability at exponential and stationary growth phases using multiple conventional techniques and statistical tools. Overall, cellular responses to various viability assays were asynchronous. Results of optical density measurement and direct cell counting were asynchronous both at exponential and stationary phases. Proliferative capacity measurement using SP-SDS indicated that cells at the end of the stationary phase were proliferative as much as exponentially growing cells. Metabolic activity assays using two different dyes concluded that the inside of cells at stationary phase is slightly less reducing compared to that of exponentially growing cells, implying that the metabolic activity imperceptibly declined as cells were aged. These results will be helpful to understand the details of yeast cell viability at exponential and stationary growth phases.

• BMB Reports
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• v.55 no.11
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• pp.519-527
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• 2022

Macrophage activation has long been implicated in a myriad of human pathophysiology, particularly in the context of the dysregulated capacities of an unleashing intracellular or/and extracellular inflammatory response. A growing number of studies have functionally coupled the macrophages' inflammatory capacities with dynamic metabolic reprogramming which occurs during activation, albeit the results have been mostly interpreted through classic metabolism point of view; macrophages take advantage of the rewired metabolism as a source of energy and for biosynthetic precursors. However, a specific subset of metabolic products, namely immune-modulatory metabolites, has recently emerged as significant regulatory signals which control inflammatory responses in macrophages and the relevant extracellular milieu. In this review, we introduce recently highlighted immuno-modulatory metabolites, with the aim of understanding their physiological and pathological relevance in the macrophage inflammatory response.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.3
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• pp.141-150
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• 2018

PURPOSE: This study was conducted to understand the adaptive responses of different modes of physical exercises utilizing skeletal muscle and the comprehensive relevance of AMPK signaling that can be activated by physical exercise as a potential molecular target in human health problems such as neuromuscular disorders (NMDs). METHODS: Most of the contents in this review article are based on recent publications concerning the main topics of interest. The reference literatures cited were obtained by basic searches of overseas academic databases such as PubMed and ScienceDirect using EndNote X7.8. RESULTS: The phenotypic adaptive responses of skeletal muscle during endurance- and resistance-based exercise training (ET and RT respectively) appear to be distinct. To explain the adaptive responses in each single mode of exercises (ET, RT) along with combined exercise training (CT), AMPK signaling is proposed as an important molecular link among those differential modes of exercise and a promising molecular target of NMDs. CONCLUSION: Based on the available evidence, intracellular AMPK signaling activated by diverse stimuli including physical exercise can be a potential and promising therapeutic target for the prevention, amelioration or cure of various human health problems including NMDs and may also be beneficial for physical rehabilitation and emergency situations that may elicit acute metabolic stresses.

• Molecules and Cells
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• v.40 no.2
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• pp.123-132
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• 2017

Insulin signaling is coordinated by insulin receptor substrates (IRSs). Many insulin responses, especially for blood glucose metabolism, are mediated primarily through Irs-1 and Irs-2. Irs-1 knockout mice show growth retardation and insulin signaling defects, which can be compensated by other IRSs in vivo; however, the underlying mechanism is not clear. Here, we presented an Irs-1 truncated mutated mouse ($Irs-1^{-/-}$) with growth retardation and subcutaneous adipocyte atrophy. $Irs-1^{-/-}$ mice exhibited mild insulin resistance, as demonstrated by the insulin tolerance test. Phosphatidylinositol 3-kinase (PI3K) activity and phosphorylated Protein Kinase B (PKB/AKT) expression were elevated in liver, skeletal muscle, and subcutaneous adipocytes in Irs-1 deficiency. In addition, the expression of IRS-2 and its phosphorylated version were clearly elevated in liver and skeletal muscle. With miRNA microarray analysis, we found miR-33 was down-regulated in bone marrow stromal cells (BMSCs) of $Irs-1^{-/-}$ mice, while its target gene Irs-2 was up-regulated in vitro studies. In addition, miR-33 was down-regulated in the presence of Irs-1 and which was up-regulated in fasting status. What's more, miR-33 restored its expression in re-feeding status. Meanwhile, miR-33 levels decreased and Irs-2 levels increased in liver, skeletal muscle, and subcutaneous adipocytes of $Irs-1^{-/-}$ mice. In primary cultured liver cells transfected with an miR-33 inhibitor, the expression of IRS-2, PI3K, and phosphorylated-AKT (p-AKT) increased while the opposite results were observed in the presence of an miR-33 mimic. Therefore, decreased miR-33 levels can up-regulate IRS-2 expression, which appears to compensate for the defects of the insulin signaling pathway in Irs-1 deficient mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.293-299
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• 1991

To investigate the effect of cooking form of rice and barley on postprandial serum glucose and insulin response in normal subject, five test carbohydrates calculated to contain 50g of glucose were consumed. Oral ingestions were divided into 5 group, i. e. dextrose(control), ground white rice, ground barley, whole white rice, whole barley, Postprandial glucose and insulin responses were measured over 3hr and showed the following pattern. Dextrose and ground white rice elicited similar postprandial serum glucose and insulin responses whereas ground barley and whole white rice intemediate, whole barley gave the lowest responses in the test group. The ground form of rice and barley were significantly higher responses than the unground form of those as well as whole white rice were higher responses whole barley, The results suggested that the cooking form of rice and barley was an important determinant of the postprandial metabolic responses.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.2
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• pp.179-186
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• 2014

Metabolomics is the study of changes in the metabolic status of an organism as a consequence of drug treatment, environmental influences, nutrition, lifestyle, genetic variations, toxic exposure, disease, stress, etc, through global or comprehensive identification and quantification of every single metabolite in a biological system. Since most chronic diseases have been demonstrated to be linked to nutrition, nutritional metabolomics has great potential for improving our understanding of the relationship between disease and nutritional status, nutrient, or diet intake by exploring the metabolic effects of a specific food challenge in a more global manner, and improving individual health. In particular, metabolite profiling of biofluids, such as blood, urine, or feces, together with multivariate statistical analysis provides an effective strategy for monitoring human metabolic responses to dietary interventions and lifestyle habits. Therefore, studies of nutritional metabolomics have recently been performed to investigate nutrition-related metabolic pathways and biomarkers, along with their interactions with several diseases, based on animal-, individual-, and population-based criteria with the goal of achieving personalized health care in the future. This article introduces analytical technologies and their application to determination of nutritional phenotypes and nutrition-related diseases in nutritional metabolomics.