Oral toxicity of malonaldehyde: a 90-day study on mice.

The oral toxicity of malonaldehyde (MA), a product of lipid peroxidation found in some foods, was investigated in a 90-d study on mice, MA as the sodium enol salt was administered in the drinking water to 8-wk-old female Swiss mice at levels calculated to provide 2, 10, 50, 250, or 500 micrograms/g body weight . d. There was no mortality and all groups gained weight at comparable rates except that those that received 500 micrograms/g body weight . d gained more slowly and lost weight after 50 d. Histopathological examination of 27 tissues indicated that the liver was the only organ that underwent dose-dependent changes. All levels of MA induced irregularities (anisokaryosis, hyperchromicity, vesiculation) of hepatic nuclei. Pancreatic lesions consisting primarily of atrophy of the exocrine cells with loss of zymogen granulation occurred in animals which received 500 micrograms MA/g body weight . d. Mild dysplasia of the urinary bladder epithelium was found in all treatment groups. Approximately 1% of the dose was excreted unchanged in the urine at each level of administration.