Detailed definition
Aromatase, encoded by the CYP19A1 gene, is the cytochrome P450 enzyme that catalyzes the final step of estrogen biosynthesis: aromatization of the A-ring of testosterone to estradiol, and of androstenedione to estrone. Aromatase is expressed in ovarian granulosa cells, placenta, adipose tissue, brain, bone, and breast. In premenopausal women, ovarian granulosa-cell aromatase produces most circulating estradiol. In postmenopausal women, with the ovary essentially silent, peripheral aromatase in fat tissue, muscle, and skin generates the bulk of circulating estrogen — which is mostly estrone. This is why higher body fat correlates with higher postmenopausal estrone levels and modestly milder vasomotor symptoms in some women. Aromatase inhibitors — anastrozole, letrozole, exemestane — are first-line adjuvant therapy for hormone-receptor-positive breast cancer in postmenopausal women, and they suppress remaining estrogen production to very low levels.
Why it matters in menopause
Two clinical scenarios make aromatase relevant to menopause care. First, women on aromatase inhibitors for breast cancer experience severe vasomotor and genitourinary symptoms because their already-low postmenopausal estrogen falls further. Second, the relationship between adipose aromatase and breast cancer risk underlies guidance on weight management in postmenopausal women, since central adiposity raises both estrogen production and breast cancer risk.
Related terms
Sources
External references: Wikipedia.