DIFFERENCES BETWEEN METABOLISM OF LINOLEIC AND PALMITIC ACID - UTILIZATION FOR CHOLESTEROL SYNTHESIS AND OXIDATION TO RESPIRATORY CO2

Measurements were made of the incorporation of intragastrically administered 1-C14-labeled linoleic and palmitic acid carbon into the total body cholesterol of the intact rat and of the rat's ability to oxidize these two labeled acids to respiratory CO2. As compared with palmitic acid, the intact rat and isolated rat tissues exhibit a greater ability to metabolize linoleic acid. This is evidenced by a greater utilization of linoleic acid carbon for synthesis of total body cholesterol and also by a preference for the oxidation of linoleic acid. The greater incorporation of linoleic acid carbon into cholesterol appears to reflect the preferential oxidation of linoleic acid by the liver, a main site of fatty acid oxidation and cholesterol biosynthesis. This preference of the rat to utilize linoleic acid carbon for the synthesis of cholesterol may help to explain the well documented observation that the plasma cholesterol of the rat increases as the linoleic acid content of the diet increases. © 1969 American Oil Chemists' Society.