The long-term administration of L-cycloserine to mice: specific reduction of cerebroside level.

Short-term experiments in which L-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 term L-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 by L-cycloserine indicating that a portion of newly synthesized galactocerebroside is shunted to synthesis of sulfatides.