Bile but not chyle lipoprotein is an important source of arachidonic acid for the rat small intestine

Abstract

Arachidonic acid (AA) functions as a structural component, eicosanoid precursor and surface material for chylomicron production in the gastrointestinal tract. The origin of this AA is poorly characterized. [ 3H]AA labelled chylomicrons and [ 14C]AA albumin-FFA were injected intravenously into biliary diverted rats and controls. Radioactivity in tissue lipids was measured after different time intervals. Output of 3H and 14C in bile was 8% of the injected dose during 24 h. Radioactivity of the upper small intestine but not of colon and stomach increased with time. Bile drain reduced the recovered amounts of radioactivity in upper small intestine by 75% after 24 h. In stomach and colon 3H/g tissue was 16–20 fold lower than in liver after 24 h. Recovery of 3H in liver was higher than of 14C. In liver 3H/g tissue was 15–40 fold higher than in stomach and colon after 10–60 min. Equilibration between AA pools of liver and other organs was not complete after 96 h. Biliary phospholipid is an important source of AA for the small intestine.