• Asian-Australasian Journal of Animal Sciences
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• 제20권7호
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• pp.1039-1048
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• 2007

Two experiments were conducted to determine whether leptin is a metabolic signal for gonadotropin secretion in ewes. In the first experiment, twenty-eight cyclic Chal ewes were assigned randomly to an energy restricted, no leptin group (ERNL) (60% of maintenance; n = 14) and an energy normal, no leptin group (ENNL) (100% of maintenance; n = 14) for 71 days (6 estrous cycles). Estrus was synchronized with seven consecutive injections of $PGF_{2{\alpha}}$ Biweekly, body weight (BW) and body condition score (BCS) were determined and blood samples were collected to measure plasma leptin concentration. Blood samples were also taken to determine plasma progesterone concentration twice weekly. After each PG injection from the second injection to the end of experiment, four ewes were selected and blood samples were collected at 20 minutes and at hourly intervals for 3 h to detect plasma LH and FSH concentration. In the second experiment, after the ceasing of the estrous cycle caused by energy restriction, six acyclic ewes were selected and randomly allotted to two groups (n = 3) and received the following treatment for four days. Ewes in an energy restricted, leptin group (ERL) were fed with a ration which provided 60% of maintenance energy requirements and intravenously injected with $4{\mu}g$ leptin/kg BW daily. Ewes in an energy excess, no leptin group (EENL) were fed with a ration that provided 180% (120%+60%) of maintenance energy requirements and intravenously injected with 1 ml saline daily. In both groups, blood samples were collected at 20 minutes and at hourly intervals for 3 h before feeding on d 0 and d 5, and for 3 h before and after injections as above on d 2 and d 4 to detect plasma LH and FSH concentration. In the first experiment, BW and BCS from the $2^{nd}$ estrous cycle, and leptin from the $3^{rd}$ estrous cycle to the end of the experiment significantly (p<0.05) decreased. In ERNL ewes, mean plasma concentrations of FSH significantly (p<0.01) decreased from the $4^{th}$ estrous cycle to d 71 and LH pulsatile secretion was suppressed on d 71, so that, mean plasma concentrations of LH (p<0.05), LH pulse frequency (p<0.01) and LH pulse amplitude (p<0.05) significantly decreased. In the second experiment, injection of leptin significantly increased mean circulating concentrations of LH (p<0.05), LH pulse frequency (p<0.01), LH pulse amplitude (p<0.05) and mean circulating concentrations of FSH (p<0.01) and leptin (p<0.01). High energy intake significantly (p<0.05) stimulated pulsatile secretion of LH and leptin secretion (p<0.01), but non-significantly increased plasma FSH concentration. The results of this study indicate that leptin is a metabolic signal for the GnRH-LH/FSH axis in feed-restricted fat-tailed ewes.

• Journal of Ginseng Research
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• 제38권2호
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• pp.83-88
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• 2014

The adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of cellular energy. Once activated, it switches on catabolic pathways generating adenosine triphosphate (ATP), while switching off biosynthetic pathways consuming ATP. Pharmacological activation of AMPK by metformin holds a therapeutic potential to reverse metabolic abnormalities such as type 2 diabetes and nonalcoholic fatty liver disease. In addition, altered metabolism of tumor cells is widely recognized and AMPK is a potential target for cancer prevention and/or treatment. Panax ginseng is known to be useful for treatment and/or prevention of cancer and metabolic diseases including diabetes, hyperlipidemia, and obesity. In this review, we discuss the ginseng extracts and ginsenosides that activate AMPK, we clarify the various mechanisms by which they achieve this, and we discuss the evidence that shows that ginseng or ginsenosides might be useful in the treatment and/or prevention of metabolic diseases and cancer.

• BMB Reports
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• 제47권3호
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• pp.158-166
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• 2014

Cell proliferation is a delicately regulated process that couples growth signals and metabolic demands to produce daughter cells. Interestingly, the proliferation of tumor cells immensely depends on glycolysis, the Warburg effect, to ensure a sufficient amount of metabolic flux and bioenergetics for macromolecule synthesis and cell division. This unique metabolic derangement would provide an opportunity for developing cancer therapeutic strategy, particularly when other diverse anti-cancer treatments have been proved ineffective in achieving durable response, largely due to the emergence of resistance. Recent advances in deeper understanding of cancer metabolism usher in new horizons of the next generation strategy for cancer therapy. Here, we discuss the focused review of cancer energy metabolism, and the therapeutic exploitation of glycolysis and OXPHOS as a novel anti-cancer strategy, with particular emphasis on the promise of this approach, among other cancer metabolism targeted therapies that reveal unexpected complexity and context-dependent metabolic adaptability, complicating the development of effective strategies.

• Journal of Microbiology and Biotechnology
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• 제19권1호
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• pp.23-36
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• 2009

In the present work, the metabolic network of primary metabolism of the slow-growing myxobacterium Sorangium cellulosum was reconstructed from the annotated genome sequence of the type strain So ce56. During growth on glucose as the carbon source and asparagine as the nitrogen source, So ce56 showed a very low growth rate of $0.23\;d^{-1}$, equivalent to a doubling time of 3 days. Based on a complete stoichiometric and isotopomer model of the central metabolism, $^{13}C$ metabolic flux analysis was carried out for growth with glucose as carbon and asparagine as nitrogen sources. Normalized to the uptake flux for glucose (100%), cells recruited glycolysis (51%) and the pentose phosphate pathway (48%) as major catabolic pathways. The Entner-Doudoroff pathway and glyoxylate shunt were not active. A high flux through the TCA cycle (118%) enabled a strong formation of ATP, but cells revealed a rather low yield for biomass. Inspection of fluxes linked to energy metabolism revealed that S. cellulosum utilized only 10% of the ATP formed for growth, whereas 90% is required for maintenance. This explains the apparent discrepancy between the relatively low biomass yield and the high flux through the energy-delivering TCA cycle. The total flux of NADPH supply (216%) was higher than the demand for anabolism (156%), indicating additional reactions for balancing of NADPH. The cells further exhibited a highly active metabolic cycle, interconverting $C_3$ and $C_4$ metabolites of glycolysis and the TCA cycle. The present work provides the first insight into fluxes of the primary metabolism of myxobacteria, especially for future investigation on the supply of cofactors, building blocks, and energy in myxobacteria, producing natural compounds of biotechnological interest.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1163-1169
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• 2004

An unstructured mathematical model is presented for lactic acid fermentation based on the energy balance. The proposed model reflects the energy metabolic state and then predicts the cell growth, lactic acid production, and glucose consumption rates by relating the above rates with the energy metabolic rate. Fermentation experiments were conducted under various initial lactic acid concentrations of 0, 30, 50, 70, and 90 g/l. Also, a genetic algorithm was used for further optimization of the model parameters and included the operations of coding, initialization, hybridization, mutation, decoding, fitness calculation, selection, and reproduction exerted on individuals (or chromosomes) in a population. The simulation results showed a good fit between the model prediction and the experimental data. The genetic algorithm proved to be useful for model parameter optimization, suggesting wider applications in the field of biological engineering.

• The Korean Journal of Physiology
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• 제11권1호
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• pp.37-44
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• 1977

In the previous study of the release, excretion, and plasma concentration of aldosterone in normal Koreans, the author found that urinary aldosterone excretion and aldosterone secretion rate of the Korean who usually take high amount of salt are significantly lower, in compared to Americans, although the plasma concentration is only tended to be low. The control of plasma aldosterone level depends on the secretion rate and the metabolic clearance of the hormone. In this experiments, the metabolic clearance rate of aldosterone was determined in normotensive korean and the effects of adrenal stimulations on the rates were also studied in the same subjects. The metabolic clearance rate of the normal Korean was not significantly different from those of the American, and shown a little increase in response to sodium restriction. These results indicate that the decrease in secretion rate rather than the increase in metabolic clearance Tate is the major factor maintaining lower plasma aldosterone level. After furosemide diuresis, on the contrary, the removal of aldosterone showed significant the decrease despite slight increase of secretion rate. This suggest that the reduction in metabolic clearance rate of the hormone during volume depletion found to be major cause of high plasma concentration. Additional potassium supply produced detectable decrease of metabolic clearance rate, but the changes were smaller than that of secretion rate, which suggested that the higher secretion rate could account for elevated plasma concentration of aldosterone rather than metabolic clearance. Above results also support author's previous evidences that the normal Korean who already adapted to a high sodium diet have ability to produce adequate aldosterone activity without producing detectable changes on the metabolic clearance rate under the condition of sodium restriction with approp riate potassium intake.

• 한국식품영양학회지
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• 제30권5호
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• pp.1048-1057
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• 2017

The purpose of this study was to compare nutrient intake, health-related factors, and risk factors for metabolic syndrome and to investigate the prevalence odds ratio according to fruit and vegetable intake among middle-aged Korean men. Subjects included 1,677 men aged 40 - 64 years. The average intake of fruits and vegetables was $578.48{\pm}5.90g/day$. Forty-nine percent of the subjects were categorized into the deficient group based on the intake of fruits and vegetables, and the other subjects were categorized into the adequate group. There was a significant difference in the nutrient density per 1,000 kcal of energy, minerals, vitamins, and dietary fiber between the fruit and vegetable intake groups (p<0.001). In terms of health-related factors, only the current smoking rate in the deficient group (57.9%) was higher than that in the adequate group (45.4%) (p<0.001). There was no significant difference in the risk factors for metabolic syndrome between the fruit and vegetable intake groups. Proportion of serum triglycerides (42.6%) was the highest at a rate that exceeded the criteria for risk factors for metabolic syndrome, but systolic blood pressure (21.7%) showed a very low rate. The fasting blood glucose, serum triglycerides, and diastolic blood pressure were significantly higher in the deficient group than in the adequate group (p<0.05). Prevalence of metabolic syndrome was 31.2%. OR for prevalence of metabolic syndrome related to fruit and vegetable intake was 1.270 times higher in the deficient group than in the adequate group (p<0.05). Also, when the daily fruit intake was increased by 100 g, the prevalence of metabolic syndrome was reduced by 0.948 times but it was not related to the vegetable intake. The results of this study can be used as the basic data to establish the guidelines for fruit and vegetable intake for prevention of metabolic syndrome in middle-aged men.

• Journal of Community Nutrition
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• 제2권2호
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• pp.135-140
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• 2000

The objectives of this study were to determine whether older Americans would provide valid energy intake information using a 24-hr recall method and to determine which characteristics were predictive of under-report of energy intake. We conducted 24-hour recalls on 83 male and 105 female community-dwelling older adults(66-87y) in the USA to assess energy(EI) and nutrient intakes. Basal metabolic rate(BMR) was calculated from age-and gender-specific equations of Schofield. Under-reporting was defined a priori as EI : BMR<0.9. Subjects volunteered demographic information, underwent depression and cognition exams, and completed a Level II Nutrition Risk Screen. Differences between under- and adequate-reporters were assessed using t-tests for characteristics and macro-nutrient profile. Stepwise regression analyses were used to predict under-reporting status. Under-reporting of EI occurred in 34% of the sample. Neither geriatric depression scale(GDS) score, nor self-reported weight loss were related to under-reporting. On average, under-reporters had higher body mass indices. The most significant variables for the main effect to predict the ratio of energy intake to estimated basal metabolic rate(EI : BMRest) were BMI and age. Using a standard cut-off of 76% of the recommended dietary allowances for Americans, under-reporters were consistently more likely to be classified as having inadequate nutrient, as well as energy, intakes. (J Community 2(2) 135∼140, 2000)

• Journal of Nutrition and Health
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• 제14권4호
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• pp.209-219
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• 1981

To evaluate long-term metabolic response of free-living Korean subjects consuming local sources adequately or slightly below habitual intake. Subjects, six male medical students aged 23-25 years were free-living, but consumed diets in the metabolic unit. They were healthy as determined from medical laborarory tests. They belong to the Korean middle-class. Temperature of outdoor during study were ranged between -2 to $26^{\circ}C$, whereas the indoor were $18-22^{\circ}C$. Animal protein ranged between 25-30% of total calorie. The three meals and a vitamin supplement to meet recommendation were given daily. Three 50day periods following the design were used to test the protein-energy adequacy of the diet. Urinary nitrogen excretion was measured daily. Fecal samples were pooled for the last 5 days of each week. Nitrogen balance was computed using 5mg N/Kg skin and miscellaneous losses. Body weight was measured daily. The study was covered on 126 metabolic observations weekly. Body weight changes were relatively stable with the energy intake of 37-44Kca1/kg, and N-balances were also relatively stable, but it was influenced by physical and or mental stress somehow. It could be assumed that the mean protein and energy requirement were $190{\pm}10mg$ N/Kg with $41{\pm}2$ Kcal/kg, and the mean digestibility of protein was 81% on these subjects with the experimental conditions. The protein requirement, however, could be cut down somewhat with some limited increaing of energy intake under parameters of N-balance and maintaining body weight. It was also observed a tendency of the requirement were getting smaller with the increase of body size.

• 대한지역사회영양학회지
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• 제15권5호
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• pp.694-703
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• 2010

Recent studies have reported that a subset of obese individuals who were metabolically healthy but obese had more favorable clinical outcomes than obese subjects with metabolic disturbances. The purpose of this study was to evaluate the distribution and agreement of obesity subtypes according to body mass index (BMI) and metabolic syndrome (MS). Furthermore, we examined the differences of nutrient intake among the groups. Data was analyzed for 1,095 female subjects older than 40 years using Korean National Health and Nutrition Survey in 2008. The degree of obesity was classified by two methods, using BMI (obese ${\geq}\;25\;kg/m^2$, not obese < $25\;kg/m^2$) and MS (meet ${\geq}\;3$ criteria among 5 index: waist circumference, triglyceride, glucose, HDL-cholesterol and blood pressure). Subjects were divided into 4 groups according to $2{\times}2$ cross table: non-obese without MS, non-obese with MS, obese without MS and obese with MS. Nutrient intakes were compared among 4 groups. The results showed that the proportions of non-obese without MS, non-obese with MS, obese without MS and obese with MS were 47.6%, 13.6%, 16.6%, and 22.2% of total subjects, respectively. The agreement (kappa value) of two methods was 0.354 (fair) in total subjects, 0.365 (fair) in 40-60 year old subjects and 0.304 (fair) in ${\geq}\;61$ year old subjects. In ${\geq}\;61$ years old subjects, intakes of percentage energy from carbohydrate, percentage of energy from fat, calcium, phosphorous, sodium, vitamin A, carotene, thiamine, riboflavin and niacin were significantly different among the groups. In contrast, the subjects of 40-60 years old, no differences in nutrient intakes were observed. In conclusion, there were differences in nutrient intakes among the groups subdivided by obesity and MS, especially in elderly female subjects. Individualized dietary guideline for subtype of obesity will be needed to treat metabolic disturbance of obesity.