AN ASSESSMENT OF GASTROINTESTINAL MUCOSAL DAMAGE IN VIVO : ENHANCEMENT OF URINARY RECOVERY AFTER ORAL ADMINISTRATION OF PHENOLSULFONPHTHALEIN IN ULCER RATS

The permeability of phenolsulfonphthalein (phenol red), a poorly absorbed drug, was examined as an index of an assessment of gastrointestinal mucosal damage. The urinary recovery after oral administration of phenol red was significantly increased in rats with indomethacin-induced ulcers. A similar result was obtained in rats with ulcers induced by restraint and water immersion stress. However, the urinary recoveries of phenol red after the intravenous administration in both types of ulcerated rats did not change compared with the controls. These findings suggest that the increase in urinary recovery of phenol red is due to increased gastrointestinal absorption. This method may be utilized as a simple, useful, and noninvasive screening test for an assessment of gastrointestinal mucosal damage in vivo.