Incorporation of label from [9, 10‐methylene‐14C] sterculic acid in rainbow trout,Salmo gairdneri

AbstractThe distribution of radioactivity from sterculic acid, labeled on the 9,10‐methylene carbon of the cyclopropene ring, was investigated in trout,Salmo gairdneri. Fifty percent of the administered dose was excreted in feces and urine by 168 hr, but less than 1% of the dose was expired as carbon dioxide during the same time period. Incorporation of radioactivity into most organs peaked at 119 hr, and the majority of the label in the liver was in the fatty acid portion of the lipid fraction. Total lipid radioactivity in liver was higher in trout conditioned to cyclopropene lipids, and a substantial amount of label was found in phosphatidylcholine and ethanolamine phospholipids as well as neutral lipid. The data demonstrate that rainbow trout readily absorb, transport and incorporate sterculic acid into tissue lipid, including membrane lipid, but cannot oxidize the methylene carbon of the cyclopropene ring to carbon dioxide.