Comparative effects of commercial Aroclors on rat liver enzyme activities

Hepatic DNA, RNA, protein and p-nitroanisole O-demethylase, aniline hydroxylase, nonspecific carboxylesterase, bromosulphophthalein-glutathione (BSP-GSH) conjugating enzyme and p-nitrophenol UDPglucuronyl transferase activities were measured in young Wistar male rats which had received intraperitoneal injections (50 mg/kg) of biphenyl and Aroclors 1016, 1221, 1232, 1242, 1248, 1254 and 1260, dissolved in peanut oil, for 3 consecutive days and assayed 96 h after the last injection. Biphenyl and all the Aroclors caused the same degree of enhancement of BSP-GSH conjugating enzyme. Decreased DNA content, increased RNA and protein content and the other enzymatic activities were related to the percent weight of chlorine and the chlorobiphenyl composition of the Aroclors. More marked effects were observed with the highly chlorinated Aroclor 1248, 1254, and 1260 mixtures which contained predominantly tetra-, penta-, hexa-, and higher-chlorinated biphenyls.