• Natural Product Sciences
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• 제18권4호
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• pp.221-226
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• 2012

Hesperidin (HES) is a bioflavonoid with antioxidant, anti-inflammatory and anti-diabetic properties. IL-6 is well known as a primary proinflammatory cytokine that contributes to impaired insulin signaling in liver. This study was to investigate whether HES improves IL-6-mediated impairment of insulin sensitivity in liver. Hepa-1c1c7 cells were pre-treated with 50 and $100{\mu}M$ HES in complete media for 1 h and then cultured in the presence or absence of IL-6 (20 ng/ml). These results demonstrated that HES restored IL-6-suppressed expression of IRS-1 protein, downregulated IL-6-increased expression of CRP and SOCS-3 mRNA, and inhibited LPS-induced production of IL-6 in Hepa-1c1c7 cells. These findings indicate that HES may ameliorate hepatic insulin resistance via improvement of IL-6-mediated impaired insulin signaling in hepatocytes.

• 수면정신생리
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• 제12권1호
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• pp.17-22
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• 2005

Sleep-disordered breathing (SDB) is associated with increased cardiovascular and cerebrovascular morbidity. Epidemiological and clinic-based studies have shown that SDB is related to impaired glucose tolerance and increased insulin resistance, independent of obesity. Despite of a consistent association between SDB and impaired glucose-insulin metabolism, the mechanism underlying this relationship has not been fully elucidated. It is recognized that hypoxemia and hypercapnia that occur in SDB provoke sympathetic nervous activity and catecholamine, epinephrine and norepinephrine, and cortisol are released. Sympathetic hyperactivity and increased catecholamines can impair glucose homeostasis by increasing glycogenolysis and gluconeogenesis, which can result in increased circulating insulin levels and increased risk of insulin resistance. A prospective study is needed to investigate the causal relationship between SDB and impaired glucose-insulin metabolism in a healthy population without diabetes, hypertension and obesity as etiologic risk factors.

• Molecules and Cells
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• 제38권4호
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• pp.297-303
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• 2015

Skeletal muscle insulin resistance, which increases the risk for developing various metabolic diseases, including type 2 diabetes, is a common metabolic disorder in obesity and aging. If potential treatments are to be developed to treat insulin resistance, then it is important to fully understand insulin signaling and glucose metabolism. While recent large-scale "omics" studies have revealed the acetylome to be comparable in size to the phosphorylome, the acetylation of insulin signaling proteins and its functional relevance to insulin-stimulated glucose transport and glucose metabolism is not fully understood. In this Mini Review we discuss the acetylation status of proteins involved in the insulin signaling pathway and review their potential effect on, and relevance to, insulin action in skeletal muscle.

• Molecules and Cells
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• 제47권3호
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• pp.100007.1-100007.11
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• 2024

Recent evidence establishes a pivotal role for obesity-induced inflammation in precipitating insulin resistance and type-2 diabetes. Central to this process is the proinflammatory M1 adipose-tissue macrophages (ATMs) in epididymal white adipose tissue (eWAT). Notably, natural killer (NK) cells are a crucial regulator of ATMs since their cytokines induce ATM recruitment and M1 polarization. The importance of NK cells is shown by the strong increase in NK-cell numbers in eWAT, and by studies showing that removing and expanding NK cells respectively improve and worsen obesity-induced insulin resistance. It has been suggested that NK cells are activated by unknown ligands on obesity-stressed adipocytes that bind to NKp46 (encoded by Ncr1), which is an activating NK-cell receptor. This was supported by a study showing that NKp46-knockout mice have improved obesity-induced inflammation/insulin resistance. We therefore planned to use the NKp46-knockout mice to further elucidate the molecular mechanism by which NKp46 mediates eWAT NK-cell activation in obesity. We confirmed that obesity increased eWAT NKp46⁺ NK-cell numbers and NKp46 expression in wild-type mice and that NKp46-knockout ablated these responses. Unexpectedly, however, NKp46-knockout mice demonstrated insulin resistance similar to wild-type mice, as shown by fasting blood glucose/insulin levels and glucose/insulin tolerance tests. Obesityinduced increases in eWAT ATM numbers and proinflammatory gene expression were also similar. Thus, contrary to previously published results, NKp46 does not regulate obesity-induced insulin resistance. It is therefore unclear whether NKp46 participates in the development of obesity-induced inflammation and insulin resistance. This should be considered when elucidating the obesity-mediated molecular mechanisms that activate NK cells.

• 한국식품영양과학회지
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• 제36권2호
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• pp.186-193
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• 2007

The prevalence of diabetes has increased to 8% of population. Unlike type 2 diabetes in the western countries, Korean diabetic patients are nonobese and have low serum insulin levels. As the increased prevalence of diabetes and the peculiar characteristics may be related to dietary fat contents, we determined their effects on insulin resistance, insulin secretion and pancreatic $\beta-cell$ mass in 90% pancreatectomized (Px) diabetic rats in the present study. The rats were provided with low fat diet (LF, 10 energy% fat), moderate fat diet (MF, 25 energy% fat) and high fat diet (HF, 40 energy% fat) for 6 months. HF increased body weight and epidydimal fat pads parallel with increased food intake compared to LF and MF. Fasting serum glucose and insulin levels and homeostasis model assessment of insulin resistance were higher in HF, compared to LF and MF, indicating that HF increased insulin resistance. Rats fed LF and MF diets reduced insulin resistance, but only rats fed MF improved pancreatic $\beta-cell$ mass and insulin secretion capacity, measured by hyperglycemic clamp and in situ pancreatic perfusion. LF had low insulin secretion capacity and pancreatic $\beta-cell$ mass, indicating the increased possibility of diabetic prevalence and progression. MF increased $\beta-cell$ mass by stimulating $\beta-cell$ proliferation and neogenesis and reducing $\beta-cell$ apoptosis. In conclusion, MF is effective for the prevention of prevalence and progression of diabetes.

• 동아시아식생활학회지
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• 제19권5호
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• pp.713-722
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• 2009

Vitamin D levels have been reported to be associated with diabetes, obesity and metabolic syndrome. There have been studies on the nutritional status of vitamin D in postmenopausal women at Seoul and premenopausal women at Busan, and these studies showed that nearly no relationship between serum vitamin D levels and the obesity index existed. However, there have been no studies that examined about the relationship between serum vitamin D levels and insulin resistance in Korea. In this study, we investigated serum vitamin D levels and the relationship between serum vitamin D levels and insulin resistance (homeostasis model assessment of insulin resistance), obesity index (body mass index, percentage of body fat and waist circumference) in 180 premenopausal women (non-obese women 87.8%, obese women 12.2%) in spring (March~April), fall (September~October) and winter (January~February) at Daejeon. Serum vitamin D levels were lower in winter than in spring-fall, after adjusting for age and the obesity index. The frequency of vitamin D inadequacy (serum vitamin D levels were $\leq$ 20 ng/mL) was 45.5% in winter and, 23.5% in spring-fall, and which showed that vitamin D inadequacy was higher in winter than in spring-fall. Multiple regression analysis showed that serum vitamin D levels had no relationship with the obesity index or insulin resistance. There was no difference in the obesity index or insulin resistance between the vitamin D inadequacy and normal group, and there was no relationship between serum vitamin D levels and the obesity index or insulin resistance in non-obese and obese premenopausal women, respectively. In conclusion, serum vitamin D levels in premenopausal women at Daejeon were lower in winter than in spring-fall, and the frequency of vitamin D inadequacy was higher in winter than in spring-fall. Serum vitamin D levels had no relationship with the obesity index or insulin resistance in premenopausal women, most of whom were not obese.

• 대한임상검사과학회지
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• 제45권4호
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• pp.131-138
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• 2013

Insulin resistance and pancreatic beta cell dysfunction have been established as being related to the diabetes. Lately, what is emphasizing is that those have been shown as something related to the metabolic syndrome and cardiovascular disease. Homeostasis model assessment (HOMA), simple index is calculated on blood levels of fasting glucose and insulin. And HOMA has been widely validated and applied for insulin resistance and pancreatic beta cell dysfunction. We also assessed the factors relative to insulin resistance and ${\beta}$ cell function determined by HOMA. The data from the 2010 Korean National Health and Nutrition Examination Survey were used. Analysis was done for 3,465 nondiabetic subjects (male 1,357, female 2,108). At baseline, anthropometric measurements were done and fasting glucose, insulin, lipid (Total cholesterol, HDL cholesterol, LDL cholesterol and Triglycerides) profiles were measured. HOMA-insulin resistance (HOMA-IR) and beta cell function (HOMA ${\beta}$-cell) were calculated from fasting glucose and insulin levels. In male, the value of HOMA-IR and HOMA ${\beta}$-cell was the highest among 30's and decreased as the age increased. In female, the value of HOMA-IR increased with age, while HOMA ${\beta}$-cell decreased. High HOMA-IR and low HOMA ${\beta}$-cell were associated with the highest value of fasting glucose and systolic blood pressure. Low HOMA-IR and high HOMA ${\beta}$-cell showed the lowest concentration of fasting glucose and the highest concentration of HDL cholesterol. High HOMA-IR and high HOMA ${\beta}$-cell were connected with BMI, Total cholesterol, LDL cholesterol, and Triglycerides. There was a negative correlation between HOMA ${\beta}$-cell and age. The correlation coefficients of HOMA-IR and HOMA ${\beta}$-cell showed the highest value among weight, BMI and WC.

• Journal of Nutrition and Health
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• 제53권4호
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• pp.356-368
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• 2020

Purpose: Histidine-containing dipeptides, which are rich in chicken, have been reported to reduce the risk of metabolic abnormalities via anticarbonylation mechanism in animal models. To determine the effect of dietary histidine-containing dipeptides on metabolic risk factors in humans, the relation between chicken consumption and insulin resistance were determined in a population consuming high carbohydrate and low protein. Methods: A total of 7,183 subjects (2,929 men and 4,254 women) aged ≥ 50 years from the Korea National Health and Nutrition Examination Survey (KNHANES) were divided into three groups according to chicken consumption (rarely, monthly, and weekly), and evaluated for the metabolic risk factors using homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) in this cross-sectional study. The fourth and fifth (IV-1-3 & V-1) KNHANES, which had blood insulin data, were chosen for the current study. Results: The chicken consumption was significantly associated with insulin (p for trend = 0.018) and HOMA-IR (p for trend = 0.023) in men. In particular, the 'weekly' chicken consuming men in the lowest tertile (< 65.0%) of carbohydrate intake group had significantly lower HOMA-IR (p for trend = 0.033) and higher QUICKI (p for trend = 0.043) than the 'rarely' intake group. In addition, the odds ratio for abnormal HOMA-IR was 0.55 (95% confidence interval [CI], 0.31-0.99) and QUICKI was 0.47 (95% CI, 0.26-0.86) for the 'weekly' chicken consuming group. Conclusion: The 'weekly' chicken consumption had a beneficial effect on insulin resistance and it may partially be due to the major bioactive components in chicken, histidine-containing dipeptides.

• Journal of Pharmaceutical Investigation
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• 제26권4호
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• pp.315-321
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• 1996

It has been indicated that problems associated with insulin iontophoresis are low bioavailability, slow absorption rate and the use of high dosage. Pretreatment of skin as a method of solving these problems was used in alloxan-induced diabetic white rabbits. Skins were treated with skin needle, electric razor, knife razor and scotch tape. Transport data shows that insulin delivery was enhanced significantly by the treatment which disrupt the barrier properties of stratum corneum. The data also shows that insulin absorption lasted for several hours after the cessation of iontophoresis. The degree of skin treatment was estimated by measuring the electrical resistance of skin. When the skins were treated with skin needle and electric razor, the standard deviations of resistance were small, which suggests the possibility of uniform delivery of insulin. The dermal responses after the invasive delivery were evaluated in accordance with OECD Guideline. It seems that electrical resistance of the skin correlate well with the dermal irritation.

• Nutrition Research and Practice
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• 제9권5호
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• pp.472-479
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• 2015

BACKGROUND/OBJECTIVES: The goal of this study was to examine the effect of Sargassum coreanum extract (SCE) on blood glucose concentration and insulin resistance in C57BL-KsJ-db/db mice. MATERIALS/METHODS: For 6 weeks, male C57BL/KsJ-db/db mice were administrated SCE (0.5%, w/w), and rosiglitazone (0.005%, w/w). RESULTS: A supplement of the SCE for 6 weeks induced a significant reduction in blood glucose and glycosylated hemoglobin concentrations, and it improved hyperinsulinemia compared to the diabetic control db/db mice. The glucokinase activity in the hepatic glucose metabolism increased in the SCE-supplemented db/db mice, while phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities in the SCE-supplemented db/db mice were significantly lower than those in the diabetic control db/db mice. The homeostatic index of insulin resistance was lower in the SCE-supplemented db/db mice than in the diabetic control db/db mice. CONCLUSIONS: These results suggest that a supplement of the SCE lowers the blood glucose concentration by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.