Endothelial cells actively concentrate insulin during its transendothelial transport

Amanda J. Genders, Vera Frison, Sarah R. Abramson, Eugene J. Barrett

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16 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)434-439
Number of pages6
JournalMicrocirculation
Volume20
Issue number5
DOIs
Publication statusPublished - Jul 2013
Externally publishedYes

Keywords

  • Endothelium
  • Insulin receptor
  • Insulin transport

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