Reconstituted human breast milk PCBs as potent inducers of aryl hydrocarbon hydroxylase

Abstract

The major polychlorinated biphenyl (PCB) components identified in human breast milk have been synthesized and a reconstituted breast milk PCB mixture representing the average levels determined in the Osaka Prefecture in Japan has been prepared. The dose effecting the half-maximal (ED50) induction of rat hepatic microsomal aryl hydrocarbon hydroxylase (AHH) for the reconstituted breast milk PCBs (ED50 ∼12 μmol·kg−1) was approximately seven times less than the ED50 for the commercial PCB mixture, Kanechlor 500. The increased biological potency of the former mixture reflects the preferential bioconcentration of the toxic PCB congeners, 2,3,3′,4,4′-penta-, 2,3′,4,4′,5-penta- and 2,3,3′,4,4′,5-hexachlorobiphenyl. © 1980, All rights reserved.