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Endothelial Cells Actively Concentrate Insulin During its Transendothelial Transport
Author(s) -
Genders Amanda J.,
Frison Vera,
Abramson Sarah R.,
Barrett Eugene J.
Publication year - 2013
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1111/micc.12044
Subject(s) - insulin , insulin receptor , endothelial stem cell , medicine , endocrinology , endothelium , inulin , receptor , chemistry , biology , biochemistry , insulin resistance , in vitro
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.