Ontogeny of CYP3A, CYP2C, and CYP2J subfamilies in human GIT
| P450 Enzymes | Quantity | Expression/Activity | Notes | ||
|---|---|---|---|---|---|
| Fetus | Neonates | Pediatric Population | |||
| CYP3A4 | mRNA | + (Miki et al., 2005; Betts et al., 2015)<x (Miki et al., 2005; Betts et al., 2015) | + (Chen et al., 2015) | + (Fakhoury et al., 2005; Chen et al., 2015) | Higher expression levels in fetus compared with adults |
| Increase during the first 3 mo after birth followed by a decrease with age to reach lower levels in older children or adults | |||||
| Protein | − (Johnson et al., 2001) | + (Johnson et al., 2001; Chen et al., 2015) | + (Johnson et al., 2001; Chen et al., 2015) | Lower expression levels in neonates and pediatric population compared with adults; increase with age | |
| Activity | − (Johnson et al., 2001) | + (Johnson et al., 2001) | + (Johnson et al., 2001) | Increase after birth with age | |
| CYP3A5 | mRNA | + (Fakhoury et al., 2009) | NA | NA | Increase with gestational age |
| CYP3A7 | mRNA | + (Betts et al., 2015) | NA | + (Fakhoury et al., 2005) | Lower expression levels compared with CYP3A4 and CYP3A5 in pediatric populations |
| Limited contribution of CYP3A7 in overall CYP3A-dependent enterocytic metabolism in children | |||||
| CYP2C8 CYP2C9 CYP2C19 | Protein | + (Cizkova et al., 2014) | NA | NA | Equivalent to adult expression levels during first or second trimester |
−, absent; NA, not assessed; +, present.