[Permeability of gastrointestinal barrier in rats for bovine serum albumin].

A study was made of the permeability of the gastrointestinal barrier of intact adult rats for bovine serum albumin (BSA) labeled with 3H during antigen administration into an isolated loop of the proximal jejunum and intragastric administration via a probe. The content of the tritium label was determined in the peripheral blood serum and liver cytoplasm obtained upon homogenate centrifugation. The content of the BSA antigenic determinants in biological fluids was determined by immunosorption. In addition, the presence of high-molecular peptides precipitated with trichloroacetic acid was also assayed in the fluids. It was demonstrated that an immunologically significant amount of BSA penetrated the internal medium of the body whatever the route of administration. In all the cases the content of BSA in the liver cytoplasm was significantly higher than in the blood serum. A considerable part of radioactivity falls within the high-molecular peptides. It is inferred that the liver plays the principal role in the deposition and catabolism of foreign antigenic structures.