Perinatal expression and inducibility of human CYP3A7 in C57BL/6N transgenic mice.

The expression and inducibility of CYP3A7 transgene in the fetus and suckling neonates from one of the transgenic lines (M10) were investigated by Northern and Western blot analyses. The mRNA expression could be detected as early as the 15th embryonic day and increased gradually with advancing gestation but then remarkably so after birth. The protein expression was also detectable postnatally and increased. Inducibility was achieved in neonatal mice via maternal exposure to zinc sulfate. Midazolam hydroxylase activities could be detected in liver microsomes prepared from 14-day-old neonates. These activities were significantly higher in transgenic than nontransgenic lines of mice (p < 0.001).