Androgen metabolism in male and female breast tissue

Incubation studies have been carried out using normal breast tissue and breast tissue from patients with gynecomastia, mammary dysplasia and breast carcinoma to determine the pattern of androstenedione metabolism. All tissues formed estrone (E₁) and testosterone (T) in all incubations. Estradiol (E₂) was isolated in incubations of tissue from 1 to 6 patients with mammary dysplasia, 5 of 6 patients with gynecomastia and in all incubations with normal and carcinoma tissue. Estrone formation was lowest in mammary dysplasia and gynecomastia, and higher in apparently normal breast tissue. The greatest E₁ formation was found in incubations with breast carcinoma tissue, although there was considerable variation within this tissue group. Estradiol formation was low in all tissues, with the highest conversion rates in carcinoma tissue. Testosterone formation in carcinoma tissue was greater than in mammary dysplasia or gynecomastia, but similar to apparently normal tissue. These results indicate that breast tissue from different pathological states varies in its capacity to aromatize androstenedione (A) to estrogenic products and to convert it to other androgens. They have also shown that the pattern of metabolism is distinctive for the nature of the pathological abnormality.