Antigen-induced decrease of salicylic acid absorption from the small intestine in actively immunized rats.

Rats were intraperitoneally immunized with bovine gamma-globulin (BGG) emulsified in incomplete Freund's adjuvant. Intestinal absorption of salicylic acid from the rat small intestine was examined by means of in situ recirculation technique. The disappearance of salicylic acid from the luminal solution was significantly decreased in rats challenged intravenously with BGG compared to saline as control. A significant decrease in absorption of salicylic acid was noted in rats immunized twice and three times, but not in rats immunized only once. The effect was maintained for at least 5 weeks after the third immunization, whereas it disappeared within 10 weeks. In normal rats, the decreased absorption of salicylic acid by the intravenous challenge with BGG was hardly observed at all. These findings suggest that the intestinal absorption of salicylic acid may be affected by systemic anaphylaxis in actively immunized rats.