Passage of Molecules through the Wall of the Gastrointestinal Tract

Abstract

A novel method for the determination of different-sized polyethylene glycols (PGE) in urine has been developed and applied to the study of intestinal permeability in man and animals. Macrogolum (PEG) 1000, a mixture of PGE ranging from 634-1338 dalton, was used as probe molecules; these could be readily extracted from urine and analyzed by reversed-phase high-performance liquid chromatography. Urinary recovery after oral intake in man and after intestinal load in rats and pigs indicates that the different-sized molecular components cross the intestinal epithelium at different rates, enabling characterization of the passive permeability properties of the mucosa. Since altered intestinal permeability could underlie the pathogenesis of various diseases, this method could be of further use in investigative and clinical gastroenterology.