Neurochemical effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Wistar and Gunn rats.

Normal Wistar, heterozygous and homozygous Gunn rats were killed one week after a single intragastric dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 20 microgram/kg in acetone-olive oil. Control animals were treated similarly but without TCDD. The brain protein and RNA content were measured together with enzyme assays of lysosomal acid proteinase and soluble DT-diaphorase. Acid proteinase activity was increased in the brains of the normal Wistar rats after TCDD treatment. RNA and protein contents were lowered in the heterozygous Gunn rats whereas no changes were detected in the homozygous Gunn rats. The cerebral soluble DT-diaphorase activity was slightly enhanced (about 35%) by TCDD treatment only in normal Wistar rats. Our results may point at modified neurotoxic effects of TCDD in chronic exposure to bilirubin as in the case of Gunn rats.