Influences of 3-methylcholanthrene, phenobarbital and dexamethasone on xenobiotic metabolizing-related cytochrome P450 enzymes and steroidogenesis in human fetal adrenal cortical cells

Aim: To explore the influence and possible mechanism of xenobiotics on adrenal steroidogenesis during fetal development. Methods: Primary human fetal adrenal cortical cells were prepared, cultured and treated with 3-methylcholanthrene, phenobarbital and dexamethasone. The activities of 7-ethoxyresorufin O-dealkylase, benzphetamine, aminopyrine and erythromycin N-demethylases were measured by enzyme assays. At the same time, quantitative analysis of steroid hormones cortisol, aldosterone, testosterone and progesterone were carried out in cultural medium by radioimmunoassays. Results: The activities of benzphetamine and aminopyrine N-demethylase were increased in the cultural fetal adrenal cells treated with phenobarbital (0.25-1 mmol/L) for 24 h. Dexamethasone (25-100 mu mol/L) also increased the activity of erythromycin N-demethylase. The activity of 7-ethoxyresorufin O-dealkylase was undetected in the cells treated without and with 3-methylcholanthrene (0.5-2 mu mol/L). Meanwhile, the contents of medium cortisol, aldosterone and progesterone were decreased after treatment with 3-methylcholanthrene. Cortisol, aldosterone and progesterone concentrations were also slightly decreased with phenobarbital. Dexamethasone enhanced the productions of cortisol and progesterone remarkably. The trend of testosterone concentration was uncertain after 3-methylcholanthrene, phenobarbital or dexamethasone treatment. Conclusion: 3-Methylcholanthrene, phenobarbital or dexamethasone could interfere with the synthesis of cortisol, aldosterone and progesterone in primary human fetal adrenal cortical cells, which likely act through xenobiotic metabolizing-related cytochrome P450 isoform activation.