OBJECTIVE: We examined insulins uptake and transendothelial transport by endothelial cells in order to: (i) ascertain whether insulin accumulates within the cells to concentrations greater than in the media; (ii) compare trans endothelial insulin transport to that of inulin (using the latter as a tracer for passive transport or leaked); and; (iii) determine whether insulins transported depended on insulin action. METHODS: Using 125I-insulin at physiologic concentrations we measured both the uptake and trans endothelial transport of insulin by bovine aortic endothelial cells and measured cell volume using tritiated 3-O-methylglucose. RESULTS: Bovine aortic endothelial cells accumulate insulin to > five-fold above the media concentrations and the trans endothelial transport of insulin, but not inulin, is saturable and requires intact PI-3-kinase and MEK signaling. CONCLUSION: The insulin receptor and downstream signaling from the receptor regulates endothelial insulin transport. Insulin is accumulated against a concentration gradient by the endothelial cell. We suggest that insulin uptake is rate limiting for insulin trans endothelial transport.
OBJECTIVE: We examined insulins uptake and transendothelial transport by endothelial cells in order to: (i) ascertain whether insulin accumulates within the cells to concentrations greater than in the media; (ii) compare trans endothelial insulin transport to that of inulin (using the latter as a tracer for passive transport or leaked); and; (iii) determine whether insulins transported depended on insulin action. METHODS: Using 125I-insulin at physiologic concentrations we measured both the uptake and trans endothelial transport of insulin by bovine aortic endothelial cells and measured cell volume using tritiated 3-O-methylglucose. RESULTS:Bovine aortic endothelial cells accumulate insulin to > five-fold above the media concentrations and the trans endothelial transport of insulin, but not inulin, is saturable and requires intact PI-3-kinase and MEK signaling. CONCLUSION: The insulin receptor and downstream signaling from the receptor regulates endothelial insulin transport. Insulin is accumulated against a concentration gradient by the endothelial cell. We suggest that insulin uptake is rate limiting for insulin trans endothelial transport.
Authors: Abeer M Mahmoud; Mohamed M Ali; Edwin R Miranda; Jacob T Mey; Brian K Blackburn; Jacob M Haus; Shane A Phillips Journal: Redox Biol Date: 2017-06-03 Impact factor: 11.799