Directional secretion of human growth hormone by genetically-modified endothelial cells

Endothelial cells, which line the lumen of blood vessels, are in a useful location to deliver proteins to the blood. The authors have studied the directional secretion of human growth hormone (hGH) by genetically-modified endothelial cells and have developed a mathematical model which can further be applied to describe the delivery of larger proteins to the circulation. By fitting experimental data to the mathematical model of their system, the authors estimate apical and basal hGH production rates of 4.3/spl plusmn/0.4 and 7.4/spl plusmn/0.5 ng/h per 1E6 cells, respectively (mean/spl plusmn/stdev, N=4).