Protein expression pattern of P-glycoprotein along the gastrointestinal tract of the Yucatan micropig

The purpose of this study is to characterize the distribution pattern of P-gp protein levels along the entire GI tract in the Yucatan micropig, which is being developed as a model for human drug bioavailability. Small and large intestines were freshly obtained and divided into about 37 segments and 10 segments, respectively (ca., 1 foot/segment). Epithelial cells from the small intestine were obtained by an elution method; whereas, a scraping method was applied to the large intestine. Total cellular protein was isolated from the epithelial cells. Western blot analysis using P-gp antibody showed that the amount of P-gp protein increased distally from the duodenum to the ileum over approximately a 10-fold range. P-gp protein in the large intestine was present at a higher level in the central portion, but the absolute amount was much less than what was found in the small intestine.