TABLE 1

Classification of sex-specific rat liver P450 genes and other genes

Genes are classified based on their response to hypophysectomy (Hx), pulsatile GH treatment of Hx rats, and continuous GH infusion in intact male rats. Male class II genes are expressed at high levels in both male and female Hx rats; they are subject to partial repression by male GH pulses (Wauthier and Waxman, 2008) and nearly complete repression by continuous GH treatment. Male class I genes, such as CYP2C11, are positively regulated by plasma GH pulses but are also repressed by continuous GH treatment, hence their increase in expression in Hx female liver to a level similar to that found in Hx male liver.

Gene Class
Prototypic Rat Genes
Loss of GH
GH Treatment
Male Hx
Female Hx
GH Pulses
GH Continuous
Male
    Class I CYP2C11 ↓ ↑ ↑ ↓
    Class II CYP2A2, CYP2C13, CYP3A2 - ↑ ↓ ↓
Female
    Class I CYP2C12, HNF6, A1BG ↓ ↓ ↓ ↑
    Class II
ADH4, IGFBP1
↑
↑
↓
↑

  • ↑, increase in gene expression compared with untreated controls; ↓, decrease in gene expression compared with untreated controls; -, no major changes in expression.