CYP3A7, fetal

P450 3 Family (Xenobioticand steroid P450 3A Subfamily CYP3A4, CYP3A5, CYP3A7 fetal CYP... 

CYP3A4, CYP3A5, CYP3A7 (fetal CYP enzyme), CYP3A43... 

Chen H, Fantel AG, Juchau MR. 2000. Catalysis of the 4-hydroxylation of retinoic acids by CYP3A7 in human fetal hepatic tissues. Drug Metab Dispos 28 1051-1057. 

The importance of these different isoenzymes is that they may catalyze different biotransformations, and this may be crucial to the toxicity of the compound in question. The isoforms found in human liver and their proportions are shown in Table 4.4. The most important subfamily is CYP3A, but there is variation in the expression of this and the other CYPs. For example, CYP3A5 is only found in 50% of human livers, and CYP3A7 is only found in the fetal liver and is switched off after birth. Even CYP3A4 shows significant interindividual variation (see also chap. 5). 

The best documented enzyme system for which decreased activity is observed in humans relates to the maturation of the CYP enzymes. In the fetal liver the CYPs 2C, lA, 2A, 2B, 3A4, 3A5, and possibly 2E are absent or present at extremely low levels, whereas CYP3A7 is actively synthesized (126,127). At birth, some of the CYP enzymes (2C, 2A, 2B, 3A4,3A5, and 2E) begin to increase in concentration for the first week, and then remain relatively constant. In contrast, the CYP1A2 enzyme seems to be expressed much later, with levels that increase during the first... 

Schuetz, J.D., S. Kauma, and P.S. Guzelian (1993). Identification of the fetal liver cytochrome CYP3A7 in human endometrium and placenta. J. Clin. Invest. 92, 1018-1024. 

Greuet, J., L. Richard, C. Bonfils, J. Domergue, and P. Maurel (1996). The fetal specific gene CYP3A7 is inducible by rifampicin in adult human hepatocytes in primary culture. Biochem. Biophys. Res. Commun. 225, 689-694. 

I. Ishii, K. Itahashi et al. (1998). Steroid hydroxy-lation by human fetal CYP3A7 and human NADPH-cytochrome P450 reductase coexpressed in insect cells using baculovirus. Res. Commun. Mol. Pathol. Pharmacol. 100, 15-28,... 

The activity of CYP3A isoenzymes in the human fetal liver is similar to that seen in adult liver microsomes. The fetal activity for CYP3A7 isoenzyme is unusual as most other fetal isoenzymes of CYP450 exhibit 5 to 40% of fhe adulf isoenzymes. Fetal and neonatal drug-metabolizing enzyme activities may differ from those in the adult. 

CYP3A7 is mainly expressed in human fetal liver, where it is the major CYP form (Kitada and Kamataki, 1994). CYP3A7 has similar catalytic... 

Pang XY, Cheng J, Kim JH, Matsubara T, Krausz KW, Gonzalez FJ (2012) Expression and regulation of human fetal-specific CYP3A7 in mice. Endocrinology 153 1453-1463... 

Greuet J, Piehard L, Bonfils C, Domergue J, Mau-rel P(1996) The fetal speeifie gene CYP3A7 is in-... 

Feeder JS, Gaedigk R, Marcucci KA, Gaedigk A, hlidal CA, Schindel BP, Pearce RE (2005) Variability of CYP3A7 expression in human fetal liver. J Pharmacol Exp Ther 314 626-635... 

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