Conjugation of androgens and estrogens by human breast tumors in vitro

The metabolism of ³H-androstenedione (Δ⁴ -A) and ³H-estriol (E³) was studied in 12 human breast tumors. Part of each tumor was analyzed for estrogen receptor content. Aliquots of tumor homogenates were incubated for 2 hr separately with ³H-δ⁴-A and ³H-E₃ in the presence of appropriate cofactors. No distinct differences emerged in the profiles of the unconjugated metabolites of ³H-δ⁴-A, the major compounds in the approximate order of descendence being androsterone, androstanedione, testosterone, 5α-androstane-3α,17β-diol, epiandrosterone, and dihydrotestosterone. One tumor homogenate from an infiltrating lobular carcinoma converted ³H-Δ⁴-A to glucosiduronate metabolites (11%), of which androsterone, 6.4%; testosterone, 1.6%; and androstanediol, 0.6% predominated. The homogenate of this tumor and two other tumors converted ³H-E₃ to ³H-E₃-3S. Conversions of E₃ to E₃-3S In the other tumor homogenates were less than 0.6%. No correlation between receptor content and the capability of the tumor to conjugate Δ⁴-A or E₃ evolved. However, correlations between steroid hormone metabolism and tumor histopathology may exist.