Regulation of the expression of two female-predominant CYP3A mRNAs (CYP3A41 and CYP3A44) in mouse liver by sex and growth hormones

A second female-predominant murine CYP3A, CYP3A44, was isolated from liver and its mRNA expression was compared with that of the previously described CYP3A41. The expression of CYP3A44 was relatively constant after birth in females, whereas it gradually declined in males after 5 weeks of age. The expression of CYP3A41 increased with age in females after 3 weeks of age, whereas it gradually declined in males after 5 weeks of age. Hypophysectomy and growth hormone replacement indicated that expression of both CYP3A mRNAs in females was dependent on the feminine plasma growth hormone profile. Estradiol induced the expression of both mRNAs and the effect was dependent on the presence of the pituitary gland. These observations suggest that endocrine control of expression might be similar, but not identical, for two female-predominant CYP3A mRNAs.