Long-chain cyclic acetals of glycerol: metabolism of the stereomeric 1,3-dioxanes and 1,3-dioxolanes in myelinating rat brain.

The metabolism of the stereomeric cyclic glycerol acetals of [1-(14)C]hexadecanal was studied in myelinating rat brain. It was found that the four isomers, cis- and trans-2-pentadecyl-5-hydroxy-1,3-dioxanes and cis- and trans-2-pentadecyl-4-hydroxymethyl-1,3-dioxolanes, were utilized by the tissue at different rates. The acetals were primarily metabolized via a ring-opening mechanism leading to palmitic acid, some of which was subsequently elongated-desaturated. Only the five-membered ring isomers were incorporated as intact acetals into both neutral and polar brain lipids.