Table 2:
Drug metabolizing enzymes expressed in the human placenta and fetal liver
| Enzyme name | Placenta | Fetal liver | ||||||
|---|---|---|---|---|---|---|---|---|
| First trimester | Second trimester | Third trimester/ term | Reference | First trimester | Second trimester | Third trimester/term | Reference | |
| CYP1A1 + | R, P, A | ND | R, P, A | 64, 148–150 | R, P, A | ND | ND | 151 |
| CYP1A2 | R | ND | P | 148, 150 | ND | ND | ND | |
| CYP1B1 | ND | ND | R | 149 | ND | ND | ND | |
| CYP2C8/9 | P, R | ND | P | 148, 152 | ND | R, A | R, A | 153 |
| CYP2D6 | R | ND | R | 148, 149 | ND | R | ND | 154 |
| CYP2E1 | R | ND | R | 64, 148, 149 | ND | ND | ND | |
| CYP2J2 | P | ND | R, P | 149, 152 | ND | ND | R | 149 |
| CYP3A4 | R | ND | R | 64, 148 | ND | R | ND | 154 |
| CYP3A5 | R | ND | R | 64, 148 | R, A | R, A | R, A | 149, 155 |
| CYP3A7 # | R | ND | ND | 148 | P, A | R, P, A | R | 82, 149, 156 |
| CYP19 | A | ND | A | 157, 158 | A | ND | ND | 157 |
| SULT1A1 | A, P | A, P | A, P | 159 | A | R, P, A | A | 71, 72, 160, 161 |
| SULT1A2 | ND | ND | ND | ND | R | ND | 72 | |
| SULT1A3 | A, P | A, P | A, P | 159 | A | R, P, A | A | 71, 72, 160 |
| SULT1B1 | ND | ND | ND | ND | R | ND | ||
| SULT1C2 | ND | ND | ND | ND | R, P | ND | 72, 161 | |
| SULT1C4 | ND | ND | ND | ND | R | ND | 161 | |
| SULT1E1 | A | A | A | 159 | ND | R, P, A | ND | 72, 161 |
| SULT2A1 | A | ND | A | 159 | ND | R, A | ND | 72, 161 |
| SULT2B1 | A | ND | R, A | 159, 162 | ND | R | ND | 161 |
| UGT1A1 | ND | ND | R, P, A | 163 | ND | R | R | 164 |
| UGT1A4 | ND | ND | R, P, A | 163 | ND | R | R | 164 |
| UGT1A6 | ND | ND | R, P, A | 163 | ND | R | R | 164 |
| UGT1A9 | ND | ND | R, P, A | 163 | ND | R | R | 164 |
| UGT2A2 | ND | ND | ND | ND | R | R | 164 | |
| UGT2A3 | ND | ND | ND | ND | R | R | 164 | |
| UGT2B4 | P | ND | R, P, | 65, 67 | R | R | 164 | |
| UGT2B7 | P | ND | R, P | 65, 67 | R | R | R | 164, 165 |
| UGT2B10 | ND | ND | R, A | 65 | ND | R | R | 164 |
| UGT2B11 | ND | ND | R, A | 65 | ND | R | R | 164 |
| UGT2B15 | ND | ND | R, A | 65 | R | R, P | R, P | 164–166 |
| UGT2B17 | ND | ND | ND | R | R | R | 164, 165 | |
| GST | ND | ND | R, A | 167 | ND | A | P | 168, 169 |
| MAO | ND | ND | R, P, A | 170–172 | ND | P, A | ND | 173 |
| X ^ | ND | ND | R, P, A | 174, 175 | A | A | A | 176 |
| PCES1 – 3 | ND | ND | R, A | 177 | ND | ND | ND | |
| CES | ND | ND | ND | ND | A | ND | 178 | |
| Peptidases | P | ND | P | 179 | ND | ND | ND | |
| Epoxide hydrolase | R, P | R, P, A | R, P | 152, 180, 181 | ND | A | ND | 181 |
R = mRNA; P = protein; A = activity was measured in microsomes, S-9, cytosol or homogenates of placental or fetal liver tissue; ND = not determined
*
- bolded enzymes are those that are likely to be functionally most important in the metabolism of drugs
#
- no change in activity/expression with gestational age, per mg protein
^
- increase in activity/expression with gestational age, per mg protein
+
- decrease in activity/expression with gestational age, per mg protein.
Enzymes with no symbol indicate that the data are not available.