Acute target organ toxicity of 1-nitronaphthalene in the rat.

1-Nitronaphthalene (1-NN) produced respiratory distress and centrilobular liver necrosis in male Sprague-Dawley rats after a single intraperitoneal injection (100 mg kg-1). Microscopic examination of the lungs of rats killed 24 h after the injection revealed a highly selective non-ciliated bronchiolar (Clara) cell necrosis as the only remarkable lesion. Pretreatment of animals with phenobarbital offered complete protection from the respiratory distress induced by 1-NN, but increased the severity of the hepatotoxicity. Pretreatment with SKF-525A protected against 1-NN-induced liver necrosis, but did not alter the incidence or severity of the respiratory distress. Under similar conditions, this pattern of toxicity was not seen with the structural analogue 2-nitronaphthalene.