The long-term administration ofl-cycloserine to mice: Specific reduction of cerebroside level

Short-term experiments in whichl-cycloserine, the inhibitor of 3-ketodihydrosphinogosine synthase, was injected subcutaneously in young mice have shown that cerebroside synthesis is inhibited specifically. Studies on the effect of long terml-cycloserine treatment on sphingolipid synthesis were performed to determine whether mice could tolerate continued cerebroside reduction and whether or not the synthesis of other sphingolipids would be inhibited.l-cycloserine, when injected at a low dose for a period of two months resulted in significantly reduced brain cerebroside level with little or no reduction in sulfatide, ganglioside, or sphingomyelin levels; liver and spleen glucocerebroside levels were also significantly reduced. The rate of cerebroside synthesis in brain was greatly reduced, whereas synthesis of sulfatides was much less affected byl-cycloserine indicating that a portion of newly synthesized galactocerebroside is shunted to synthesis of sulfatides.