- Effect of Adipose Differentiation-Related Protein (ADRP) on Glucose Uptake of Skeletal Muscle.
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Yun Hyi Ku, Min Kim, Sena Kim, Ho Seon Park, Han Jong Kim, In Kyu Lee, Dong Hoon Shin, Sung Soo Chung, Sang Gyu Park, Young Min Cho, Hong Kyu Lee, Kyong Soo Park
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Korean Diabetes J. 2009;33(3):206-214. Published online June 1, 2009
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DOI: https://doi.org/10.4093/kdj.2009.33.3.206
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 Abstract
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- BACKGROUND
Skeletal muscle is the most important tissue contributing to insulin resistance. Several studies have shown that accumulation of intramyocellular lipid is associated with the development of insulin resistance. Thus, proteins involved in lipid transport, storage and metabolism might also be involved in insulin action in skeletal muscle. Adipose differentiation-related protein (ADRP), which is localized at the surface of lipid droplets, is known to be regulated by peroxisome proliferator activated receptor gamma (PPARgamma). However, it is not known whether ADRP plays a role in regulating glucose uptake and insulin action in skeletal muscle. METHODS: ADRP expression in skeletal muscle was measured by RT-PCR and western blot in db/db mice with and without PPARgamma agonist. The effect of PPARgamma agonist or high lipid concentration (0.4% intralipos) on ADRP expression was also obtained in cultured human skeletal muscle cells. Glucose uptake was measured when ADRP was down-regulated with siRNA or when ADRP was overexpressed with adenovirus. RESULTS: ADRP expression increased in the skeletal muscle of db/db mice in comparison with normal controls and tended to increase with the treatment of PPARgamma agonist. In cultured human skeletal muscle cells, the treatment of PPARgamma agonist or high lipid concentration increased ADRP expression. siADRP treatment decreased both basal and insulin-stimulated glucose uptake whereas ADRP overexpression increased glucose uptake in cultured human skeletal muscle cells. CONCLUSION: ADRP expression in skeletal muscle is increased by PPARgamma agonist or exposure to high lipid concentration. In these conditions, increased ADRP contributed to increase glucose uptake. These results suggest that insulin-sensitizing effects of PPARgamma are at least partially achieved by the increase of ADRP expression, and ADRP has a protective effect against intramyocellular lipid-induced insulin resistance.
- Common Genetic Polymorphisms in the Promoter of Resistin Gene are Major Determinants of Plasma Resistin Concentrations in Humans.
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Young Min Cho, Byung Soo Youn, Sung Soo Chung, Ki Woo Kim, Bo Kyeong Koo, Kang Yeol Yu, Hong Je Park, Hyoung Doo Shin, Hak Chul Jang, Kyong Soo Park, Seong Yeon Kim, Hong Kyu Lee
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Korean Diabetes J. 2004;28(1):9-19. Published online February 1, 2004
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Abstract
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- BACKGROUND
Resistin has been postulated to be an important link between obesity and insulin resistance. Genetic polymorphisms in the resistin gene promotor have been suggested as a determinant of the expression of resistin mRNA, which is possibly associated with obesity and insulin resistance. In this study, the association between the genotype of the resistin promoter, and its plasma concentrations, were investigated. METHODS: The g.-537A>C and g.-420C>G polymorphisms in the resistin promoter were examined, and the levels of plasma resistin measured in the Korean subjects, both with and without type 2 diabetes. Haplotype-based promoter activity and the gel electrophoretic mobility-shift assays(EMSA) were also performed. RESULTS: The -420G and the -537A alleles, which were in linkage disequilibrium, were associated with higher plasma resistin concentrations. Individuals with the A-G(-537 A and -420G) haplotypes showed significantly higher plasma resistin levels than those that did not. The haplotypes A-G had modestly increased promoter activities compared to the other haplotypes. The EMSA revealed the -420 G allele to be specific for binding of the nuclear proteins from adipocytes and monocytes. However, neither polymorphism was associated with type 2 diabetes or obesity in our study subjects. CONCLUSION: Polymorphisms in the promoter of the resistin gene are major determinants of plasma resistin concentrations in humans
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