Methapyrilene induces membrane lipid peroxidation of rat liver cells

Male Sprague Dawley rats were fed either a basal diet or the same diet containing 0.1% methapyrilene hydrochloride for 1, 2 and 3 days and 1 and 2 weeks. Peroxidative degradation of membrane lipids from liver cell mitochondria and microsomes was evaluated by determining the extent of diene conjugate (u.v. absorption 233 nm) formation. Feeding methapyrilene for 1, 2 and 3 days resulted in lipid peroxidation of both mitochondrial and microsomal membranes. After 1 and 2 weeks feeding, peroxidation was no longer evident in lipids isolated from mitochondria, while the microsomal membrane lipids showed persistent conjugated dienes. The results suggest that membrane lipid peroxidation of the liver may play a role in the promoting and/or carcinogenic effects of methapyrilene hydrochloride.