Biological measurement of estrogenic activity in urine and bile conjugates with the in vitro ER-CALUX reporter gene assay

摘要

Although estrogens are excreted as biologically inactive conjugates, they can be reconverted to an active form, possibly by bacteria. A simple method was developed to deconjugate estrogen metabolites present in human urine and fish bile back to active estrogens by enzymatic hydrolysis with β-glucuronidase or live Escherichia coli cells. Deconjugated extracts were tested for estrogenic activity in the in vitro stable estrogen receptor-mediated chemical-activated luciferase gene expression(ER-CALUX) assay. Estrogen glucuronides in urine obtained from human males and females were effectively converted to active forms after incubation with β-glucuronidase or E. coli.