Changes produced by a cholesterol-biosynthesis inhibitor, trans-1,4-bis-(2-chlorobenzylaminomethyl)cyclohexane dihydrochloride (AY-9944), in the total fatty acids in the liver and brain, and in phospholipids in the serum, liver, heart, brain and lungs from male rats, have been studied. 2. Treatment with AY-9944 produced the following changes in the fatty acid composition: (a) a marked decrease in the percentage of linoleic acid and an increase in oleic acid in the total fatty acids in the liver; (b) in the serum, an overall decrease in the percentage of linoleic acid in neutral lipids and phospholipids; (c) an increased content of linoleic acid in the beta-acyl chain of phosphatidylcholines in the liver and in sphingomyelins in the brain and lungs; (d) an increased content of palmitic acid and oleic acid in the beta-acyl chain of phosphatidylcholine in the liver, heart and lungs; (e) an increased content of phosphatidylcholines and sphingomyelins, together with an increased percentage of saturated fatty acids in these phosphatides in the lungs. 3. Changes in the phosphatides and the production of foam cells in the lungs suggest that AY-9944 may be of use in the study of the alveolar membrane.
