- Effect of Gi-proteins on Insulin Binding, Internalization and Recycling of Insulin Receptor in Bovine Aorta Endothelial Cell.
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Hyuk Ho Kwon, Hyun Shik Son, Jung Min Lee, Seung Hyun Ko, Ok Ki Hong, Sung Dae Moon, Sang Ah Chang, Kun Ho Yoon, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
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Korean Diabetes J. 2003;27(1):26-38. Published online February 1, 2003
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- BACKGROUND
Guanine nucleotide binding proteins (G-proteins) play important roles in the hormonal actions of many signal transduction systems. Possible roles for the Gi-protein in insulin action have been suggested. It is reported that Gi-protein is associated with insulin actions to a greater extent than Gs-protein. There are at least three different subtypes of Gi-proteins (Gi(alpha1), Gi(alpha2), and Gi(alpha3)), however, it is not certain which subtypes are associated with insulin receptors and their action. METHODS: To investigate the effects of Gi-proteins on insulin action, the Gi-proteins were overexpressed in cultured bovine aortic endothelial cells (BAEC), using the DNA-polylysine-adenovirus complex transfection method. After incubating for 24 hours, the BAEC were treated with 200 ng/mL insulin to evaluate the insulin binding, receptor internalization and recycling. RESULTS: The following results were found : 1) The binding of specific insulin bindings to the insulin receptors of endothelial cells were time-dependent, reaching their maximal levels in all cells after 30 minutes. The maximal specific bindings of the control, Gi(alpha1), Gi(alpha2), and Gi(alpha3) were 0.58+/-0.1, 0.54+/-0.08, 0.54+/-0.1, 0.53+/-0.09%, respectively. 2) The internalization of 125I-insulin, into endothelial cells, was assessed by the acid washing dissociation method, and occurred rapidly. There was a significant difference in the internalized radioactivity of the 125I-insulin in the overexpressed Gi(alpha2) protein group compared to the two groups. 3) The recycling of the insulin receptors in the three types of Gi-protein showed no significant difference between the three group. CONCLUSION: In conclusion, the Gi(alpha2) protein may be associated with internalization of the insulin-insulin receptor complex, and appears to be important in both the action of insulin and the intracellular processing of insulin receptors.
- Prevalence of micro and macroalbuminuria in relation to hypertension and chronic diabetic vascular complications among type II diabeticpatients.
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Hyuk Ho Kwon, Je Ho Han, Jong Min Lee, Soon Jip Yoo, Hyun Sik Son, Kun Ho Yoon, Moo Il Kang, Jwan Soo Hong, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Ku Kang
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Korean Diabetes J. 1992;16(4):317-324. Published online January 1, 2001
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- No abstract available.
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