The Fate of Dietary Wax Esters in the Rat.

Oleyl palmitate fed to rats as 15% of the diet was partly absorbed and partly excreted as a mixture of wax ester, free fatty acid, and free alcohol. Because of purgative effects, animals caged together contaminated each other's fur with fecal lipid, giving them an appearance of seborrhea. Animals given oleyl alcohol as 4% of the diet did not show purgative effects but excreted lipid which was similar in composition to that excreted by rats given wax esters. Thus both hydrolysis and synthesis of waxes can occur in the intestine. Similar reactions have been carried out in vitro in the presence of a pancreatic enzyme. Wax ester and free oleyl alcohol were detected in the liver after feeding either compound, and in both cases the predominant ester was oleyl palmitate. The question of whether oleyl alcohol is absorbed in the free or esterified form was not satisfactorily resolved.