DOLICHOL DEPOSITION IN DEVELOPING MAMMALIAN BRAIN - CONTENT OF FREE AND FATTY-ACYLATED DOLICHOL AND PROPORTION OF SPECIFIC ISOPRENOLOGUES

Dolichol serves a critical role in N-linked glycoprotein synthesis as the carrier of saccharide moieties. The deposition of dolichol was investigated in developing rat brain. The contents of both the free and fatty-acylated forms of dolichol as well as the specific isoprenologues of dolichol were determined. Two distinctive phases of rapid dolichol deposition were observed. The 1st during brain development, and the 2nd, with aging. The predominant form of brain dolichol was the free derivative at all ages; however, during the 2 phases of rapid deposition of total dolichol, fatty-acylated dolichol became detectable and increased transiently. The rapid rate of increase of brain dolichol during development occurred later than that of brain cholesterol, which shares a common biosynthetic pathway with dolichol. The peak rate of increase of dolichol occurred at 25 days postnatal, and of cholesterol, at 18 days postnatal. A distinct ontogenetic alteration in the proportion of the individual molecular species (isoprenologues) of dolichol also was defined. Dolichol seems particularly involved in developmental events of the 3rd-6th postnatal wk in rat brain, e.g., myelination and synaptogenesis.