Glucose does not influence the insulin-like growth factor (JGF) binding to carrier proteins (IGFBPs): analysis of rat and human serum by western ligand blotting
Autor: | Stefano Cianfarani, Jeffrey M P Holly, Martin O. Savage, V. J. Frost |
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Rok vydání: | 1993 |
Předmět: |
Male
Proteases medicine.medical_specialty medicine.medical_treatment Blotting Western Endogeny Insulin-like growth factor-binding protein Cellular and Molecular Neuroscience Insulin-like growth factor Somatomedins Internal medicine medicine Animals Humans Binding site Rats Wistar Molecular Biology Pharmacology Protease biology Cell Biology Somatomedin Rats Insulin-Like Growth Factor Binding Proteins Endocrinology Glucose Biochemistry Insulin-like growth factor 2 biology.protein Molecular Medicine Carrier Proteins hormones hormone substitutes and hormone antagonists |
Zdroj: | Experientia. 49(8) |
ISSN: | 0014-4754 |
Popis: | The insulin-like growth factors (IGFs) circulate bound to specific proteins (termed IGFBP-1 through IGFBP-6) that modulate IGF bioactivity in tissues. The aim of this study was to analyse the effects of glucose on IGF binding to IGFBPs in rat and human serum by means of western ligand blotting. Serum samples were incubated with increasing concentrations of glucose (0 to 50 mmol/l), and EDTA (25 mmol/l) was added to inhibit protease activity. To analyse the effect of glucose on protection of IGFBPs from protease activity, serum from pregnant women (reported to be very rich in proteolytic activity against IGFBPs) was added to rat serum previously incubated with glucose. Glucose did not affect the 125I-IGF binding to rat and human serum IGFBPs. The intensity of IGFBP-3 bands decreased considerably during the incubation. This appeared to be due to endogenous protease activity, since the decrease was blocked by addition of EDTA. The incubation of rat serum with pregnant human serum produced a marked attenuation of IGFBP-3 and disappearance of IGFBP-4 bands. In conclusion, our study shows that glucose does not influence the IGF binding to IGFBP-3 either in rat or in human serum, confirms the presence of endogenous proteolytic activity in normal non-pregnant serum, and demonstrates that glucose has no protective action against protease activity. |
Databáze: | OpenAIRE |
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