Effects of feeding ethyl-dihomo-γ-linolenate on rabbit renomedullary lipid composition and prostaglandin production in vitro

Abstract

Feeding the ethyl ester of dihomo-γ-linolenic acid for 25 days to rabbits resulted in increased PGE₁ (20to30-fold) and PGE₂ (1.5-fold) output by a hormone responsive, in vitro, renal papilla preparation. The relative amount of PGE₁ increased from <5% of PGE₂ in controls to 25–35% of PGE₂ in the papillae of 20∶3ω6-supplemented animals. During the study renomedullary triglycerides in the 20∶3ω6-supplemented animals increased 2.8-fold compared to animals fed an equal amount of a control fatty acid mixture, and in addition to a marked enrichment in 20∶3ω6, also contained increased proportions of 20∶4ω6 and longer chain polyenes. The increase in triglyceride content found in the renal medulla was not seen in the renal cortex or liver. There was no increase in renomedullary phospholipid content during the study, and phopholipids of treated animals contained increased proportions of 20∶3ω6 and 20∶4ω6, but not longer chain polyenes. The results indicate that enriching the prostaglandin precursor pool by feeding 20∶3ω6 can alter the type and amount of prostaglandin released by the renal papilla, at least in vitro. Also, the selective changes in amount and long chain polyene content of renomedullary triglycerides during the study suggest some special functions for this lipid class in prostaglandin precursor metabolism. *** DIRECT SUPPORT *** A00M6131 00010