Biochemical and cytogenetic effects in rats caused by short‐term ingestion of aroclor 1254 or firemaster BP6

Male rats were fed either 0, 5, 50, or 500 ppm Aroclor 1254 (ARO) or Firemaster BP6 (FM) mixed in ground rat chow for 2, 3, or 5 wk. The relative biological response to the two chemicals sometimes varied with dose level. For example, for some parameters FM caused a greater effect than ARO at the 5 and 50 ppm levels, but not at the 500 ppm level, where, presumably, the maximum response was attained. The experimental design did not permit a totally unambiguous comparison of all the responses to ARO and FM. Some apparent differences in biochemical responses determined at sacrifice may have been partly due to the fact that, for the 3 wk study, rats were exposed to FM 48 hr longer than to ARO, and thus the comparison of ARO and FM toxiclties should be considered tentative. The following evaluations were made, based on the assumption that this 2 day difference had no effect. Relative kidney and testis weights, hematology, SGPT, SGOT, BUN, plasma corticosterone, rate of liver protein synthesis per gram of tissue...