Lipid metabolism and oxygen consumption in a hereditary demyelinating neuropathy, the trembler mouse: an in vitro...

Sciatic nerves from 15-day-old trembler and control mice were maintained in vitro up to 53 h and the metabolism of myelin lipids and the oxygen consumption were investigated [35S]Sulfate was incorporated into sulfatides at a higher rate and turned over more rapidly in trembler nerves than in controls. [14C]Galactose was incorporated into cerebrosides of trembler nerves at a lower rate and turned over like the controls. In contrast, synthesis of sulfatides labeled with [14]galactose was increased in mutants and no significant turnover was observed for both trembler and control nerves during the whole incubation period. Similar results were obtained using [3H]serine as a precursor and no significant differences were observed in the turnover rates of sphingomyelin and phosphatidylcholine between trembler and control nerves. These data suggest the presence of two different pools of cerebrosides, a small one formed by the fast recycling of sulfatides and which does not mix with a second, larger one. The rate of oxygen consumption did not change significantly during the incubation period and was 2-3-fold higher in trembler nerves than in controls, reflecting, at least partly, the increased sulfatide metabolism.