Androstenedione metabolism in epithelial cells derived from early-lactation human milk

Epithelial cells derived from duct epithelium were cultured from early lactation human milk in medium supplemented with 15% fetal and amikacin (50 μg/ml). The capacity of these cells to metabolize androstenedione to estrone, estradiol and C 19 metabolites was studied during continuous culture. After extraction of the medium, the products were subjected to phenolic partition and separated by thin-layer and paper chromatography, followed by recrystallization to constant specific activity. The study demonstrated a progressive increase in the formation of estrone and testosterone over the first 24 h in culture, while estradiol formation showed an initial 2–4 h lag, then increased slowly. The C 19 compounds identified were androsterone, 5 α-androstanedione, epiandrosterone, dihydrotestosterone and etiocholanolone. 5 α-Androstanedione and androsterone were the major 5 α-reduced metabolites. Since these cells are derived from normal duct epithelium, their metabolic characteristics may be more representative of normal breast tissue than those of tissue removed from patients with pathological breast disorders.