Practice question

Atrazine is chlorotriazine herbicide widely applied to corn crops known to impair male reproductive development in amphibians. Mechanism involves induction of cytochrome P450 aromatase enzyme encoded by CYP19A1 converting androgens testosterone and androstenedione to estrogens estradiol and estrone in developing gonad. Elevated local estrogen feminizes testis, causes testicular oocytes, skewed sex ratios and reduced testosterone. Transcriptional upregulation via orphan nuclear receptor SF-1 increases aromatase promoter activity. This shift in steroidogenesis toward estrogen synthesis disrupts androgen-dependent male differentiation pathway illustrating endocrine disruption through increased estrogen production rather than direct estrogen receptor agonism alone.