ANTI‐WHOLE WHITE MATTER SERUM INHIBITS INCORPORATION OF GLUCOSE AND GALACTOSE INTO THE LIPIDS OF MYELINATING SPINAL CORD CULTURES

Myelin formation was inhibited in fetal mouse spinal cord cultures in the presence of serum from rabbits with experimental allergic encephalomyelitis produced by inoculation of whole bovine spinal cord white matter in complete Freund's adjuvant. Controls were exposed to decomplemented serum. Replacement of serum in inhibited cultures on the 18th day in vitro (DIV) with control serum (disinhibited) resulted in the appearance of visible myelin within 2–3 days. From 20 to 23 DIV, d‐[U‐¹⁴C]glucose or d‐[U‐¹⁴C]galactose was present in all media. Total protein, DNA, gangliosides and galactolipids were reduced by 21% in inhibited cultures, and activity of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase was reduced by 50%. There was little reduction in the incorporation of glucose carbon (21–23 DIV) into several lipid classes examined. Labelling of cerebrosides by galactose carbon in inhibited cultures was only 12% of that of controls while there was no reduction in the labelling of neutral lipid–cholesterol and the glycerophosphatides. Galactolipid labelling by [¹⁴C]galactose in the disinhibited cultures was intermediate between inhibited and control cultures. Differences in the effects of inhibiting medium on the incorporation of glucose and galactose carbon indicate that ceramide synthesis is less affected than is galactose incorporation to form cerebroside.