Insulin Degradation In Vitro and In Vivo: A Comparative Study in Men: Evidence That Immunoprecipitable, Partially Rebindable Degradation Products Are Released From Cells and Circulate in Blood
| Autor: | G. Di Cianni, Luca Benzi, R. Navalesi, Alessandro Pilo, Annamaria Ciccarone, P Cecchetti |
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| Rok vydání: | 1994 |
| Předmět: |
Male
Radioisotope Dilution Technique Time Factors Endocrinology Diabetes and Metabolism Metabolite medicine.medical_treatment In Vitro Techniques Iodine Radioisotopes chemistry.chemical_compound Reference Values In vivo Internal Medicine medicine Humans Insulin Chromatography High Pressure Liquid biology Monocyte Metabolism In vitro Kinetics Insulin receptor medicine.anatomical_structure chemistry Biochemistry Injections Intravenous Leukocytes Mononuclear biology.protein Intracellular |
| Zdroj: | Diabetes. 43:297-304 |
| ISSN: | 1939-327X 0012-1797 |
| DOI: | 10.2337/diab.43.2.297 |
| Popis: | The products of insulin metabolism generated in vitro and in vivo were compared in this study. Monocytes from 10 control subjects were incubated with 125IA14-labeled insulin, acid washed, and solubilized or reincubated in insulin-free binding buffer to study both intracellular radioactivity or radioactivity released from cells to medium. To evaluate in vivo insulin metabolism, labeled insulin (100–120 μCi) was injected as a single intravenous bolus in 5 of the 10 subjects. Cellular and plasma radioactivity was characterized by high-performance liquid chromatography (HPLC). The results of the study show the following: 1) Products with superimposable HPLC elution profiles are found within cells and in medium. Two new labeled products are observed in the latter, suggesting that a membrane degradation process exists in monocytes. 2) Intermediates found within monocytes, in medium from monocytes, and in plasma have identical elution profiles, supporting the possibility that insulin is metabolized in various cells by a common pathway. 3) Insulin metabolism produces intermediates that bind well to anti-insulin antibody. The presence in plasma of these products induces a significant difference in the value of the metabolic clearance rate of insulin when HPLC or immunoprecipitation is used to detect intact insulin. 4) Immunoprecipitable products maintain, in part, the capacity to bind to insulin receptors and to be internalized into monocytes. |
| Databáze: | OpenAIRE |
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