Organ distribution and toxicity of lignin.

It is suggested that 125I-labeled natural and synthetic lignins administered orally to mice are absorbed through the digestive tract and excreted via urine, in addition to feces. Intravenous administration of lignins produced preferential accumulation of radioactivity in the liver and also in the stomach tissue and lung. It also induced an increase in the spleen weight (splenomegaly), suggesting that the immune system might be stimulated. Lignin significantly increased the heme oxygenase among several hepatic enzymes. Macroscopical examination of mice which were administered a lethal dose of lignin showed nasal and lung congestion leading to hemorrhage.