- 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
- The Effects of Insulin Sensitizers on the Plasma Concentrations of Adipokines in Type 2 Diabetic Patients.
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Hye Seung Jung, Young Min Cho, Kyung Won Kim, Byung Soo Youn, Kang Yeol Yu, Hong Je Park, Chan Soo Shin, Seong Yeon Kim, Hong Kyu Lee, Kyong Soo Park
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Korean Diabetes J. 2003;27(6):476-489. Published online December 1, 2003
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Abstract
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- BACKGROUND
Resistin, leptin and adiponectin are proteins secreted from adipose tissue, and have been suggested to play roles in insulin sensitivity. The effects of the circulating levels of two different types of insulin sensitizer, rosiglitazone and metformin, in type 2 diabetic patients were examined to elucidate the relationship between adipokines and insulin resistance. METHODS: Thirty type 2 diabetic patients, who showed poor glycemic control when administered 4 mg glimepiride a day, without severe diabetic complications or medical illness, were randomized to receive an additional 4mg rosiglitazone or 1000 mg metformin a day. The plasma resistin, leptin and adiponectin concentrations were measured at the baseline and after 6 months of treatment. The anthropometric parameters, fasting plasma glucose, HbA1C, total cholesterol, triglyceride, HDL-cholesterol and free fatty acids were also measured. Certain single nucleotide polymorphisms of adipokine genes were also identified. RESULTS: There were no significant differences in the reductions of the plasma glucose and HbA1C levels, after 6 months of treatment, between the two groups. The plasma resistin concentrations decreased, the adiponectin significantly increased and the leptin showed a tendency to increase in the rosiglitazone group. In the metformin group, only the resistin concentration significantly increased. However, the changes in the adipokines did not correlate with the HOMA-IR in either group. The reduction in the HbA1C due to rosiglitazone was greater if the initial leptin level was high, if there was a G allele on the -420th locus of the resistin gene, or the 45th locus of the APM1 (adiponectin gene) was the T-homozygote or there was a T allele on the 276th locus of the APM1. Those due to metfromin were greater with high initial adiponectin levels. CONCLUSION: In type 2 diabetic patients, showing poor glycemic control with sulfonylurea therapy, rosiglitazone or metformin treatment changed some of the adipokine concentrations, but these changes were not clearly related with insulin resistance. Polymorphisms of certain adipokine genes seem to have a relation to the susceptibility of rosiglitazone.
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