On the Biosynthesis of Plasmalogens during Myelination in the Rat, VIII. Incorporation of 1-[1-14C]Alkyl-2-acyl-3-sn-glycerophosphoethanolamine with Different Fatty Acids

Abstract

The uptake of 14C labeled alkyl chains into the alkenyl chains of plasmalogens was estimated 12, 24, 48 and 72 h after intracerebral administration of different substrates to 14 day old rats. 1-[1-14C]alkyl-3-sn-glycerophosphoethanolamines, containing in the 2-position of the glycerol residue a stearoyl (I), an oleoyl (II), an archidonoyl (III), a 4,7,10,13,16,19-docosahexaenoyl (IV) or no acyl residue (substrate V, so-called lysoether phosphatide) were used as substrates. If the fatty acid in the 2-position of the substrate is a saturated one (I), the recovery of radioactive alkyl chains is relatively high, but their desaturation is very slow and seems not to reach its maximum even after 72 h. If a substrate with an unsaturated fatty acid in the 2-position is applied, the number of radioactive chains (alkyl plus alkenyl) depends on the chain length and/or the number of double bonds in the fatty acids. The desaturation of the alkyl chains, however, reaches its maximum about 48 h after application (except for substrate IV). The recovery of radioactivity in the glycerophosphoethanolamine lipids is the highest in experiment V at any time; the total activity of the alkenyl chains reaches a maximum 24 h after application.