1. Differential effects of IGF-I, IGF-II and insulin in human preadipocytes and adipocytes – Role of insulin and IGF-I receptors
- Author
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Peter Strålfors, Karolina Bäck, Cecilia Brännmark, Hans J. Arnqvist, Department of Clinical and Experimental Medicine, Division of Cell Biology, and and Linköping Diabetes Research Centre
- Subjects
DNA Replication ,medicine.medical_specialty ,glucose metabolism ,medicine.medical_treatment ,education ,Carbohydrate metabolism ,Biochemistry ,Receptor, IGF Type 1 ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Insulin-Like Growth Factor II ,Internal medicine ,Insulin receptor substrate ,growth factors ,Adipocytes ,medicine ,Humans ,Immunoprecipitation ,Insulin ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,Insulin-Like Growth Factor I ,Phosphorylation ,Receptor ,hybrid receptors ,Molecular Biology ,Cells, Cultured ,030304 developmental biology ,0303 health sciences ,DNA synthesis ,biology ,receptor activation ,Chemistry ,Receptor, Insulin ,IRS2 ,Insulin receptor ,Glucose ,Adipogenesis ,030220 oncology & carcinogenesis ,biology.protein ,Protein Binding ,Thymidine - Abstract
We compared insulin and IGF effects in adipocytes expressing IR (insulin receptors), and preadipocytes expressing IR and IGF-IR (IGF-I receptors). Treatment of adipocytes with insulin, IGF-II or IGF-I resulted in phosphorylation of IR. Order of potency was insulinIGF-IIIGF-I. In preadipocytes IR, IGF-IR and insulin/IGF-I hybrid receptors (HR) were detected. Treatment of preadipocytes with IGF-I and IGF-II 10(-8)M resulted in activation of IGF-IR and IR whereas insulin was more potent in activating IR, with no effect on IGF-IR. In adipocytes glucose transport was 100-fold more sensitive to insulin than to IGFs and the maximal effect was higher with insulin. In preadipocytes glucose accumulation and DNA synthesis was equally sensitive to insulin and IGFs but the maximal effect was higher with IGF-I. In conclusion, insulin and IGF-I activate their cognate receptors and IGF-I also HR. IGF-II activates IR, IGF-IR and HR. Insulin and IGF-I are partial agonists to each other's receptors.
- Published
- 2011
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