Persistence of 2,3,6-substituted pentachlorobiphenyls in the lung parenchyma: a new structure-dependent tissue localization of polychlorinated biphenyls in mice.

Whole body autoradiograms of mice injected with 2,2',3,3',6-[14C]pentachlorobiphenyl (I), 2,3,3',4',6-[14C]pentachlorobiphenyl (II), 2,2',3,5',6-[14C]pentachlorobiphenyl (III) and 2,3',4,5,5'-[14C]pentachlorobiphenyl (IV) showed a specific accumulation of I-III in the lung parenchyma, whereas IV did not accumulate in the lung tissue. The results suggest that chlorobiphenyls with chlorine atoms in the positions 2,3,6 possess a specific affinity for the lung parenchyma. These chlorobiphenyls differ in chemical structure from those which are accumulated in the bronchial mucosa and those which are not taken up in the respiratory tract. The importance of in vivo metabolism in the determination of structure activity relationships is stressed.