The metabolism of 4,7,10,13,16-[5-14c]docosapentaenoic acid in the testis of the rat

The metabolism of [5-14C]docosapentaenoic acid, produced biosynthetically from [1-C]linoleic acid, was studied in rat testis at various time intervals after intratesticular injection. 14C-Labeled palmitic acid isolated from testicular total fatty acids indicated that significant catabolism of the intratesticularly injected [14C]docosapentaenoic acid had occurred. A significant proportion of the recovered radioactivity could be traced as arachidonic acid, which was shown by chemical degradation to have been biosynthesized in rat testis by the direct biohydrogenation and cleavage of the [5-14C]docosapentaenoic acid. 48 h after injection, 71% of the radioactivity recovered in the total fatty acids was in docosapentaenoate, 8% in arachidonate, and 5% in palmitate. These were present predominantly in esterified form as phosphatides and triglycerides.