Metabolism of ether linked glycerolipids in dogfish (Squalus acanthias) serum: Evidence for resistance of ether bond to cleavage in 1-alkyl-2,3-diacylglycerols

Abstract

Rac-[1-¹⁴C]-palmitylglycerol (chimyl alcohol), rac-[1-¹⁴C]-palmityl-2,3-dioleoylglycerol, and rac-palmityl-2,3-[9, 10-³H]-dioleoylglycerol were incubated with dogfish (Squalus acanthias) serum for periods of up to 15.0 hr. The ether bond of the carbon 14 labeled chimyl alcohol was cleaved readily, and radioactivity was incorporated into free fatty acids and the acyl chains of the major glycerolipids of the serum. In sharp contrast, the ether bond of the corresponding dioleoyl derivative remained virtually intact. However, the tritium from the acyl chains was incorporated into glycerolipids via intermolecular rearrangements of fatty acids. The findings are consistent with previous findings with rat liver microsomes showing that the ether linkages of alkylglycerolipids are resistant to oxidative cleavage when acyl groups are present on the glycerol moiety. However, substantial differences may exist between the conditions required for oxidative cleavage of the ether linkage of alkylglycerols in mammals and primative fish.