An in Vitro System for the Study of Myelin Synthesis¹

A system for the study of short‐term myelin synthesis in spinal cord tissue in vitro with [U‐ 14 C]glucose as a lipid and protein precursor is described. The rates of lipid and protein incorporation into myelin are age‐dependent, but do not appear to behave similarly. Uptake of labelled carbon is most rapid in monophosphoinositide and lecithin, and slowest in cerebroside sulphate. Myelin protein seems to retain more metabolic activity than does the lipid. These findings are interpreted as support for the unit membrane hypothesis for myelin rather than the subunit model.