Part 1 of Essay
SUMMARY Investigations of the integrity and transport characteristics of 2/4/A1 cells have been done in this report. The cell line was isolated from rat fetal intestinal epithelial cells and transfected with thermolabile SV40 large T antigen. These cells proliferated at 33 °C, but eliminated the antigen and ceased prolife ....

Part 2 of Essay
.... to the small intestine. In transport studies 2/4/A1 cell line monolayers selectively restricted the permeation of hydrophilic permeability markers proportional to molecular weight and discriminated more accurately between the molecules of intermediate molecular weight compared to Caco-2 cells. These results indicated that 2/4/A1 cells could be used as a model for hydrophilic drug absorption. INTRODUCTION The small intestine plays a crucial role in the absorption of drugs and nutrients. Exogenous substan ....