GM_3对小鼠腹腔巨噬细胞磷脂代谢转换率的影响

神经节苷脂ＧＭ_３对小鼠腹腔常驻巨噬细胞（Ｒ－Ｍ）和Ｇｅ－１３２体内激活的巨噬细胞（Ｇｅ－１３２－Ｍ）的磷脂代谢转换有显著的影响，当这两种Ｍ在体外用ＧＭ_３处理时，表现出［￣（３２）Ｐ］Ｐｉ和［￣３Ｈ］肌醇参入ＰＩ降低，参入ＰＩＰ、ＰＩＰ_２增加；但在［￣（３２）Ｐ］Ｐｉ和［￣３Ｈ］胆碱参入ＰＣ上，Ｒ－Ｍ与Ｇｅ－１３２－Ｍ不同，即ＧＭ_３促进同位素前体参入Ｒ－Ｍ的ＰＣ，抑制它们参入Ｇｅ－１３２－Ｍ的ＰＣ．以上结果表明ＧＭ３可能提高了ＰＩ或ＰＩＰ的磷酸激酶的活性，致使［￣（３２）Ｐ］ＰＩＰ和［￣（３２）Ｐ］ＰＩＰ_２增多，［￣（３２）Ｐ］ＰＩ减少．激活的Ｍ（Ｇｅ－１３２－Ｍ）本身ＰＣ代谢转换率较Ｒ－Ｍ高，当Ｇｅ－１３２－Ｍ再受ＧＭ_３刺激，ＰＣ代谢转换率降低，这提示ＧＭ_３对激活的Ｍ的ＰＣ代谢转换有调节作用．

The Effect of GM_3 on Phospholipid Turnover of Mouse Peritoneal Macrophages

Ganglioside GM_3 showed marked in vitro effect on the phospholipid turnover of mouse peritoneal macrophages (M) including resident M (R-M) and Ge-132 in vivo activated M(Ge-132-M) . Both M s showed decreased incorporation of ￣(32)P]Pi & ￣3H]inositol into phosphatidylinositol (PI) and increased incorporation of ￣(32)P] Pi &. ￣3H] inositol into polyphosphoinositides (PIP and PIP_2) elicited by in vitro GM_3 treatment; but showed different incorporation rate into phosphatidylcholine (PC ), i. e., increased incorporation of ￣(32)P]Pi &. ￣3H]choline into PC of R-M, while for PC of Ge-132-M, the incorporation was decreased. These results suggest that GM_3 could possibly activate the phosphokinase of PI and PIP, thus accounting for the decrease in the radioactivity of PI and the increase in that of PIP and PIP_2. The PC turnover rates of activated M(Ge-132-M) became faster than that of the unstimulated one(R-M), but when Ge-132-M was treated in vitro with GM_3 it showed a decrease in PC turnover rates. The results show that GM_3 may regulate PC turnover of activated M.