• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.398-407
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• 2020

The inhibitory effect on α-glucosidase, a marker of postprandial hyperglycemia, and angiotensinconverting enzyme (ACE), a marker of hypertension, was analyzed using non-fermented green tea and three different types of fermented tea, which are popular beverages in modern life. Green tea was mixed with trace amounts of vanadate (50 ㎍/mL), which has insulin-mimetic effects, to investigate the synergistic effect of vanadate on the inhibition of α-glucosidase. The concentration of epigallocatechin gallate (EGCG) and caffeine was also checked. The extracts of green tea and fermented teas showed clear inhibition on α-glucosidase, which caused a decrease in the postprandial glucose levels. The inhibitory effect was most prominent in the 20% fermented tea. Trace amounts of vanadate (50 ㎍/mL)-mixed green tea extract had twice the inhibitory effect on α-glucosidase than the pure tea extract. All teas showed inhibitory effects on ACE. Among those, the effect was most prominent in green tea, which had higher concentrations of EGCG. In contrast, the postprandial glucose-lowering effect and ACE inhibition of the fermented teas, which have a lower level of EGCG, was attributed to some other different functional substances.

• Clinical and Experimental Pediatrics
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• v.48 no.5
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• pp.481-487
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• 2005

Purpose : Adiponectin, adipose tissue-specific protein, has anti-inflammatory and anti-atherogenic properties. It has been found to have a negative correlation with obesity and to play a role in modulating glucose tolerance and insulin sensitivity. Serum adiponectin concentrations are decreased in adults with obesity and type 2 diabetes. We investigated the difference in adiponectin levels between obese and non-obese children, and evaluated the relationship of serum adiponectin with body mass index(BMI), serum fasting insulin, lipid profiles and homeostasis model assessment(HOMA) in children. Methods : We measured serum adiponectin levels by radioimmunoassay in 113 children(82 obese children and 31 non-obese controls) from 8 to 15 years of age, and also checked BMI, fasting serum glucose, insulin and lipid profiles. Fasting and postprandial serum adiponectin concentrations were compared by oral glucose tolerance tests in 27 obese children. The correlations of adiponectin with BMI, insulin, low density lipoprotein(LDL)-cholesterol and HOMA were analyzed by Pearson's correlation. Results : The serum adiponectin levels were significantly lower in the obese group(19.7 mg/mL) than in the non-obese group(27.5 mg/mL)(P<0.01). Serum adiponectin concentrations were negatively correlated with BMI(r=-0.39, P<0.01), serum insulin(r=-0.28, P<0.01), LDL-C(r=-0.20, P<0.01) and HOMA(r=-0.22, P<0.01). At oral glucose tolerance tests in obese children, postprandial 2 hours adiponectin level(19.8 mg/mL) was decreased compared to fasting level(25.8 mg/mL)(P<0.01). Conclusion : Serum adiponectin concentrations were inversely related to adiposity and insulin resistance in children. We suggest the serum adiponectin level could be used as an early marker of insulin resistance in obese children.

• The Korean Journal of Nuclear Medicine
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• v.18 no.1
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• pp.39-44
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• 1984

It is well known that glucagon, like insulin, is very important in the moment-to-moment control of the homeostasis of glucose, and of amino acids. Glucagon has been shown to have potent glycogenolytic, gluconeogenic and lipolytic activities. Attention to its role in the pathogenesis of diabetes mellitus and hypoglycemia has been also advanced recently. To evaluate the diurnal variation of plasma glucagon concentration, we measured serum glucose, insulin, and plasma glucagon every 30 minutes or every hour in 7 normal Korean adults. Results were as follows: 1) Although plasma glucagon concentration showed wide individual variations, it had a tendency to decrease after meals. After lunch and dinner, plasma glucagon concentration had gradually declined and reached its nadir at postprandial 2-2.5 hours. The minimal level of plasma glucagon was at 4 A.M. 2) Serum insulin:plasma glucagon ratios were increased promptly after meals. Especially after lunch, its peak was prominent $(3.65{\pm}1.95)$. The minimal level of serum insulin:plasma glucagon ratio appeared at 6 A.M.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.185-194
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• 2018

The different polymorphisms of the transcription factor 7-like 2 (TCF7L2) gene promote variances in diabetes susceptibility in humans. We investigated whether these genotypes also promote differences in diabetic susceptibility in commercial pigs. Growing pigs (Landrace, both sex, 50-60 kg) with the C/C (n=4) and T/T (n=5) TCF7L2 genotypes were identified and intravenously injected with streptozotocin (STZ, 40 mg/kg) twice in weekly intervals, then a high-energy diet was offered. Oral glucose tolerance tests, blood analyses and the homeostasis model assessment-insulin resistance (HOMA-IR) index calculations were performed. The animals were sacrificed at the end of 12 weeks of treatment to reveal the pancreas histomorphometry. The results showed that all of the treated pigs grew normally despite exhibiting hyperglycemia at two weeks after the induction. The glycemic level of the fasting or postprandial pigs gradually returned to normal. The fasting insulin concentration was significantly decreased for the T/T carriers but not for the C/C carriers, and the resulting HOMA-IR index was significantly increased for the C/C genotype, indicating that the models of insulin dependence and resistance were respectively developed by T/T and C/C carriers. The histopathological results illustrated a significant reduction in the pancreas mass and insulin active sites, which suggested increased damage. The results obtained here could not be compared with previous studies because the TCF7L2 background has not been reported. Growing pigs may be an excellent model for diabetic in children if the animals are genetically pre-selected.

• Biomolecules & Therapeutics
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• v.29 no.4
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• pp.419-426
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• 2021

In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branched-chain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.

• Korean Journal of Pharmacognosy
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• v.51 no.1
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• pp.1-29
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• 2020

Diabetes mellitus, commonly known as diabetes, is a group of metabolic disorders characterized by high blood sugar levels over a prolonged period. Diabetes has been found to show many acute complications such as cardiovascular disease, stroke, chronic kidney disease, foot ulcer and damage to eyes. Korean ginseng (Panax ginseng) has been traditionally known to normalize the functional deficiencies of the lung, spleen and stomach, and thus improve the secretion of body fluids, thereby quenching thirst, suggesting it to be effective in the treatment of diabetes. Experimental studies (in vitro and in vivo) have recently shown that Korean ginseng and its extracts exhibit antidiabetic effects, and also insulin secretion and sensitizing effects related to blood glucose control. Moreover, clinical trials on antidiabetic effects of Korean ginseng have been reported to show blood glucose control, improvement of insulin resistance, reduction of postprandial blood glucose level and improvement of serum lipids (TG, TC, LDL-C). These will be critically examined by means of in vitro studies, cell experiment, animal models and human trials with a focus on understanding of molecular mechanisms.

• Journal of Nutrition and Health
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• v.31 no.7
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• pp.1139-1150
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• 1998

The purpose of this study is to investigate the effects of the silkworm powder on blood levels of glucose, Hb Alc, insulin, and lipids. Thirty-one NIDDM patients from Kyung Hee Medical Center were divided into two groups : patients with silkworm powder supplements and drug treatments(Drug diabetes) and patients with silkworm powder supplement only(Non-drug diabetes). For the control group, age-matched subjects were recruited. During the 4 weeks of the experimental period, silkworm powder(500mg/mea1) was given to the subjects right after each meal. Nutritional assessments and dietary education were carried out periodically, and body weight and blood pressure were measured when patients visited the hospital. Overnight fasting and 2-h postprandial blood glucose levels were measured at 2 week intervals. The blood levels of insulin, Hb Alc, and lipids were measured before and after the supplements. The mean ages of the three groups were 56.7-59.6 years old. The height, weight, and BMI did not differ among the groups. The fasting blood glucose levels were 138.1$\pm$22.0mg/dl for the Drug treated diabetes group, 175.0$\pm$32.0mg/dl for the Non-drug diabetes group, and 108. 3$\pm$16.gmg/dl for the control group at the begining of the supplement. After 4-wks of supplements, the blood levels of glucose tended to decrease in all three experimental groups. Before the supplements, the 2-h postprandial blood glucose levels of the Drug diabetes, Non drug diabetes, and control groups were 244.7$\pm$62.6mg/dl, 272.4$\pm$40.1mg/dl, and 147.7$\pm$28.0mg/dl, respectively. After the supplement, the levels were 197.2$\pm$30.gmg/dl, 208.6$\pm$ 56.6mg/dl, and 151.3$\pm$30.3mg/dl, respectively. This shows that silkworm powder tended to lower blood levels by 19.4% and 23.4% in NIDDM patient groups. However, the changes in the blood levels of insulin, Hb Alc, ind lipids were not observed after the supplement. In conclusion, the present study has demonstrated that silkworm powder has a tendency to decrease 2-h postprandial blood glucose levels, but it should be used with caution in controlling the diabetes. (Korean J Nutrition 31(7) 1139-1150, 1998)

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.827-835
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• 2009

Insulin has crucial roles in energy metabolism in all mammals but has been less studied in ruminants. An experiment was conducted to investigate the effects of hypoinsulinemia induction on appetite, performance, carcass composition and blood metabolite levels in sheep. Treatments were intravenous injection of four doses of streptozotocin; 0, 25, 50 and 75 mg/kg BW named C, L, M and H, respectively. Twenty male lambs were divided into four treatment groups. Animals in group H could not continue the experiment because of abnormalities. The duration of the experiment was eight consecutive weeks, and injection was performed at the end of week 3. Feed and water intakes were measured weekly and weight changes of animals were recorded and used for calculation of other growth parameters. Blood samples were collected weekly via venipuncture at fasting and 2.5 h post-prandial and analyzed for hormones and blood metabolites. Results showed a marked hypoinsulinemia in group M with significant decrease in fasted and postprandial insulin concentrations and also fasted leptin concentrations vs. the control group C (p<0.05). Group M showed significant increases in blood glucose, triglycerides, cholesterol, total protein, blood urea nitrogen and ketone body levels vs. group C (p<0.05). After injection, animals in group M showed diabetic hyperphagia and enhanced water intake as compared to group C (p<0.05) but, despite increased feed intake, they did not gain more weight than controls (p<0.05), and consequently, their feed conversion ratio was greater. Protein and fat contents of meat and liver were not significantly different among groups (p>0.05). In conclusion, the results suggested a regulatory role of insulin in energy metabolism of ruminants by exerting two opposing effects; central catabolic and peripheral anabolic.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.1048-1057
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• 1994

Nonobese NIDDM patients were studied were studied with respect to changes in visceral protein status, serum glucose and lipids and insulin secretion capacity before and after intake of enteral formula. Patients with renal or hepatic disease, gastrectomy, malabsorption, weight gain over past 6 months and poorly controlled blood glucose level were excluded. Eighteen patients served as case and administered, in addition of their usual diet, 400ml of enteral formula for 8 weeks. Another 18 patients participated in controls and had usual food intake for 8 weeks. In the begining, the levels of fasting and postprandial glucose, glycated hemoglobin, triglyceride, HDL, LDL, total cholesterol, albumin, total protein and transferrin and glucose response area on oral glucose tolerance test were not different between two groups. The response areas of insulin, C-peptide and free fatty acid and serum IGF-1 level were higher in the case than in the control group. Energy intake of patients given enteral formula exceeded their estimated energy requirements(108%) and they consumed a mean of 112g protein per day. Patients given enteral formula showed an increase in body weight(4.4%), serum transferrin(10%), IGF-1(13%) and triglyceride(34%) while controls showed no changes in those parameters at 8 weeks compared to initial values. There were no significant changes after 8 weeks in the levels of glucose, glycated hemoglobin, HDL, LDL, total cholesterol, total protein and albumin and response areas of glucose, insulin, C-peptide and free fatty acid in both groups compared to initial values. This study suggests that nutrition supplement with enteral formula can increase body weight and visceral protein status in nonobese NIDDM patients without changes in blood glucose. However, excessive calorie intake could temporarily increase serum triglyceride. In addition, this study indicates that serum transferrin and IGF-1 are more sensitive indicators to changes of protein intake than serum albumin and total protein.

• Nutritional Sciences
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• v.8 no.2
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• pp.97-103
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• 2005

The goal of this study was to investigate abnotmalities in camitine metabolism present by determining blood camitine and lipid concentrations in Korean diabetic patients. The study subjects included 108 Korean diabetic patients (64 males and 44 females) who were hospitalized in Chonbuk National University Hospital and 27 subjects were also hospitalized as non-diabetic controls (10 males and 17 females). Glucose, total cholesterol, triglyceride (TG) and HDL-cholesterol in plasma were enzymatically assayed and insulin was measured by immunoradiometric assay. Nonesterified camitine (NEC), acid-soluble acylcarnitine (ASAC), and acid-insoluble acylcarnitine (AIAC) were determined by a modified radioisotopic method Glucose and insulin levels were significantly elevated in diabetic patients compared with controls. Total cholesterol was elevated in female but not male diabetic patients and triglycerides were elevated both in male and female diabetics. Plasma and urinary total carnitine (TCNE) were significantly elevated in diabetics as compared with normal controls. In male diabetics, NEC concentrations were significantly elevated above controls, but not in female subjects. Plasma NEC and TCNE concentrations were significantly increased in male diabetics, but significantly decreased in female diabetics. All urinary carnitine concentrations were significantly increased in diabetics as compared with controls. Urinary NEC concentrations were four times higher in male diabetics and three times higher in female diabetics than in controls. The ratios of serum and urinary acylcarnitine/NEC were also significantly higher in diabetics than in controls. This study suggested that there was a remarkable abnormality in lipid and carnitine metabolism in Korean diabetic patients, and the further study on carnitine metabolism and the effects of carnitine supplementation for Korean diabetic patients are needed.