Metabolism of diethylstilbestrol in hamster hepatocytes

Under certain modulating conditions the liver of the male Syrian golden hamster is a target organ for the carcinogenic effect of the synthetic estrogen diethylstilbestrol (DES). As a basis for mechanistic studies aimed at elucidating the role of metabolic activation in the process of DES-induced neoplasia, the metabolism of 14C-DES was investigated in freshly isolated hamster hepatocytes. These oxidative metabolites of DES, viz. Z,Z-dienestrol,3'-hydroxy-DES and 1-hydroxy-E-DES, were formed in 14.2, 9.1, and 0.3% yield, respectively, when hepatocytes were incubated with 50 nmol DES/mg cellular protein for 60 min. Glucuronides (4.0%) and sulfates (2.8%) of DES and of the oxidative metabolites were also found, and non-extractable binding of radioactivity to cellular protein was observed indicating the formation of reactive intermediates. The capability of hamster hepatocytes to oxidize and conjugate DES should allow the investigation of the effects of modulators on the metabolic activation of DES in this cellular system in order to help clarify the mechanisms of DES-induced hepatocarcinogenesis.