RAPID TRANSPORT OF BIOLOGICALLY INTACT INSULIN THROUGH CULTURED ENDOTHELIAL CELLS

Abstract

Mono A₁₄-[¹²⁵I].iodoinsui in was incubated with cultured endothelial cells derived from bovine pulmonary arteries at physiologic conditions. The processing of the cell-bound A₁₄-[^l25I]-iodoinsulin was evaluated by trichloroacetic acid precipitation, gel filtration and high performance liquid chromatography. In contrast to insulin processing in many other cell types, approximately 95% of cell bound insulin was dissociated from the cells in <15 minutes, and biologically intact insulin rapidly passed through the endothelial cells. The unique location of endothelial cells coupled withthe ability of rapid transport of intact insulin are consistent with an endothelial role for either the transport of insulin out of the bloodstream or as an extrapancreatic storage area for insulin.