Biological Effects of Polychlorinated Biphenyls in Rats and Quail

Estrogenic activity was assessed by determining the stimulation of the uterine glycogen response of the immature rat uterus 18 hours after administration of the test compound(1). The potency of active compounds is reported in terms of the minimal subcutaneous dose which will increase glycogen to a level significantly different from control. In a series of 11 polychlorinated biphenyls and terphenyls, the compounds containing up to 48% chlorine were estrogenically active (Table 1). A polychlorinated terphenyl containing 42% chlorine was found to be 8 times more active. This is a low level of estrogenic activity and probably arises from hydroxylated metabolites during in vivo metabolism.