Compositions of the three test solutions used for the intestinal permeability studies
| Hypo-osmolar (12 mmol/l) | Iso-osmolar (244 mmol/l) | Hyperosmolar (1500 mmol/l) | |
| 3-0-methyl-d-glucose | 0.2 g | 0.2 g | |
| d-xylose | 0.5 g | 0.5 g | |
| l-rhamnose | 1.0 g | 1.0 g | 1.0 g |
| Lactulose | 5.0 g | 5.0 g | |
| 51Cr-EDTA | 50–100 μCi | ||
| Glycerol | 9.2 ml |
Inclusion of 3-0-methyl-d-glucose allows assessment of active carrier mediated transport and d-xylose passive carrier mediated transport.
l-rhamnose assesses “small pore” predominantly non-mediated transcellular transport and lactulose and51Cr-EDTA assess non-mediated “large pore” paracellular transport.33 The differential urinary excretion of51Cr-EDTA/l-rhamnose or lactulose/l-rhamnose provides a specific index of intestinal permeability.