Glucuronidation of 1-naphthol in the rat intestinal loop

The glucuronidation of 1-naphthol after its instillation into the intestinal lumen was studied in closed or single pass perfused jejunal loops by measuring the appearance of 1-naphthol glucuronide in the intestinal lumen and in venous blood. Within 30 min 69% of 1-naphthol instilled into the jejunal loop was metabolized almost exclusively to the glucuronide; 49% was in venous blood and 20% in the intestinal lumen. After instillation of 1-naphthol glucuronide, 59% was left in the intestinal lumen and 20% appeared in venous blood. When the intestine was perfused with 1-naphthol, 91% of the naphthol absorbed from the intestinal lumen was glucuronidated at a rate of 6.7 nmole/min/g tissue; 82% of the glucuronide was released into the blood under steady state conditions. The results demonstrate the suitability of this system for studies on drug metabolism in intact intestinal tissue.