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Mouse glomerular endothelial cells have an insulin receptor
S J Elliot1, F G Conti, L J Striker
1Renal Cell Biology Group, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland.
Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme
|November 1, 1990
Summary
Scientists found insulin receptors on mouse glomerular endothelial cells, similar to other microvascular beds. Receptor levels decreased with insulin exposure but were reversible, indicating potential therapeutic insights.
Area of Science:
- Endocrinology
- Cell Biology
- Nephrology
Background:
- Insulin receptors are crucial for glucose metabolism.
- Endothelial cells play a vital role in microvascular function.
- Understanding insulin receptor characteristics in glomerular endothelial cells is important for kidney health.
Purpose of the Study:
- To investigate the presence and characteristics of insulin receptors on cloned mouse glomerular endothelial cells.
- To determine the binding affinity and regulation of these receptors.
- To compare the findings with insulin receptors in other microvascular endothelial cells.
Main Methods:
- Cloning of mouse glomerular endothelial cells.
- Insulin binding assays using radiolabeled insulin.
- Scatchard analysis to determine receptor affinity.
- Down-regulation studies with prolonged insulin exposure.
- Covalent cross-linking and SDS-PAGE to identify receptor subunits.
- Assessment of insulin-stimulated beta-subunit phosphorylation.
Main Results:
- Insulin receptors were identified on mouse glomerular endothelial cells.
- High and low affinity binding sites were characterized with specific dissociation constants (Kd).
- Receptor down-regulation was observed after insulin exposure, with reversible effects.
- SDS-PAGE revealed a band at Mr 125,000, consistent with the insulin receptor.
- Insulin stimulated phosphorylation of the beta subunit.
Conclusions:
- Mouse glomerular endothelial cells possess insulin receptors with characteristics similar to other microvascular endothelial cells.
- These receptors exhibit both high and low affinity binding and are subject to down-regulation.
- The findings suggest a conserved role for insulin signaling in different microvascular endothelial cell types.