Female-predominant rat hepatic P-450 forms j (IIE1) and 3 (IIA1) are under hormonal regulatory controls distinct from those of the sex-specific P-450 forms.

TLDR: These studies demonstrate that these female-predominant hepatic P-450 enzymes are regulated by different mechanisms, and that both are under hormonal regulatory controls distinct from those that govern expression of the female-specific hepatic enzymes.

Abstract: Hepatic expression of cytochrome P-450j (alcohol- inducible nitrosamine demethylase; P-450 gene IIE1) and P- 450 3 (testosterone 7α-hydroxylase; P-450 gene IIAl) is female predominant in adult rats [female/male = 1.5-2 (P-450j) or 3-4 (P-450 3)]. This sex difference emerges during the postsuckling period, when P-450 3 declines significantly (60-70% decrease) in male, but not female, rats, and P-450j declines in both sexes, but to a lower constitutive level in males than in females. The biochemical factors and regulatory events that control these developmental changes were investigated and found to be distinct from those that regulate expression of the female-specific hepatic enzymes P-450 2d (P-450 gene IIC12) and steroid 5α-reductase. Immunoquantitation of the changes in P-450j and P- 450 3 levels in hormonally altered rats established that both P- 450s are under gonadal control. However, while androgen and estrogen both suppress P-450j expression, estrogen stimulates and androgen suppresses the expressi...