Abstract
1. [5,6-14C]Eicosa-5,8,11,14-tetraynoic acid administered intravenously to the rat was rapidly metabolized probably mainly by the β- and ω-oxidation pathways. Carbon number extrapolation was used to assign probable structures to some of the metabolites observed.
2. Two minutes after administration eicosa-5,8,11,14-tetraynoic acid and one metabolite were observed in plasma, and at 15 min after administration three metabolites and the parent compound were observed in liver. The probable structure of the metabolite in plasma and one of those in liver was hexadec-3,6,9,12-tetrayn-1,18-dioic acid.
3. In the bile-duct cannulated rat four metabolites, but no eicosa-5,8,11,14-tetraynoic acid, were excreted equally distributed between phosphatidyl ethanolamine and phosphatidyl choline in the phospholipid fraction of bile. Three of the metabolites had the probable structures octadec-3,6,9,12-tetraynoic acid, octadec-3,6,9,12-tetrayn-1,18-dioic acid and hexadec-3,6,9,12-tetrayn-1,16-dioic acid.
4. A low level (2.8%) of metabolism of the tetra-acetylenic moiety was indicated from respired 14CO2 measurements.