1. Functional and biochemical studies were performed on the small intestine of control rats, and the results were compared with similar studies on animals given triparanol at a dosage of 0114 mmol/kg daily for 10 days. The animals given triparanol were fed with either standard rat food or a gluten-free diet.
2. By using a recirculating-perfusion technique in vivo, it was shown that absorption of galactose from an 8 mmol/l solution was impaired in the ileum but not in the jejunum of the triparanol-treated rats.
3. Assays of marker enzymes for the principal subcellular organelles were performed on isolated jejunal and ileal enterocytes. In the ileum there was a striking decrease in lysosomal enzyme activities and a smaller but significant decrease of lactate dehydrogenase, catalase and malate dehydrogenase activities. In the jejunum there was no significant change in the activities of these enzymes.
4. Measurements of lysosomal integrity indicated that ileal lysosomal fragility was markedly increased and that jejunal lysosomes were affected to a much smaller extent.
5. These effects of triparanol could not be ameliorated by feeding with a gluten-free diet.