Neutral glycosphingolipids were isolated from the colon of rats between birth and adulthood. The glycolipid concentration was stable during this period. Epithelial cells of the adult colon contained three times more glycolipids than the whole organ. The distribution pattern underwent only minor modifications during development. Free ceramide contributed for 23–27of the total neutral sphingolipids at all ages. In 6-day-old rats, it was constituted of nonhydroxylated fatty acids linked to C18-sphingenine (57.3of the bases), CC18-and C20-4D-hydroxysphinganine (24.2 and 14.0of the bases, respectively). This composition was essentially maintained during development. Glucosylceramide was the major glycolipid at all ages (40–50of the total neutral sphingolipid content). At birth, 40of its fatty acids were 2-hydroxylated and 93of the bases were C18-4D-hydroxysphinganine. In adult epithelial cells, 75of the fatty acids were 2-hydroxylated and CC18-and C20-4D-hydroxysphinganine contributed for 66 and 25of the bases, respectively. A transient increase of the contribution of nonhydroxylated fatty acids and C18-sphingenine was observed during the first week of life. C20-4D-hydroxysphinganine, which was characterized by gas-liquid chromatography of its aldehydes after periodate oxidation and of itsN-acetyl O-trimethylsilyl derivatives, appeared alter birth and reached 20of the bases after two weeks. These findings are another example of the specificity of the lipidic part of glucosylceramide during the ontogenic differentiat
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