CHANGES OF ADENYLATE-CYCLASE ACTIVITY IN AH-130 ASCITES HEPATOMA OF YOSHIDA INDUCED BY ENRICHMENT WITH FATTY-ACIDS

Enrichment of hepatoma cells with arachidonic acid increases fluidity of plasma membranes, unstimulated lipid peroxidation and basal adenyla te cyclase activity, whereas enrichment with stearic acid decreases fl uidity and does not cause any variation in lipid peroxidation or adeny late cyclase. The increase in adenylate cyclase activity may be due to the increase not only in fluidity, but also in lipid peroxidation pro ducts. Indeed, adenylate cyclase is stimulated by 4-hydroxynonenal, on e important product of lipid peroxidation, when added to plasma membra nes. 4-hydroxynonenal increases adenylate cyclase two-fold in unenrich ed plasma membranes and three-fold in plasma membranes enriched with a rachidonic acid in comparison with basal activity. (C) 1995 Academic P ress, Inc.