Distribution of total CYP content, CYP3A4 activity, and microsomal content along a representative human small intestine
| Segment | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Microsomal protein (mg) | 162 | 73 | 32 | 28 | 14 | 13 |
| P-450 content (nmol/mg) | 0.12 | 0.14 | 0.14 | 0.10 | 0.02 | 0.03 |
| Erythromycin N-demethylase activity (nmol/min/mg) | 0.85 | 1.07 | 0.90 | 0.38 | 0.34 | 0.39 |
Human small intestine segments 1 to 6 were prepared as described in the legend to Fig. 3. Microsomes, prepared from each segment, were used to determined CYP content and erythromycin N-demethylase activity as described in the legend to Fig. 3.