LIPOPROTEIN-LIPASE SUPPRESSION IN 3T3-L1 CELLS BY AN ENDOTOXIN-INDUCED MEDIATOR FROM EXUDATE CELLS
LIPOPROTEIN-LIPASE SUPPRESSION IN 3T3-L1 CELLS BY AN ENDOTOXIN-INDUCED MEDIATOR FROM EXUDATE CELLS
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DOI：
10.1073/pnas.79.3.912
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
CERAMI, A
中科院分区：
文献类型：
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作者：
KAWAKAMI, M;PEKALA, PH;CERAMI, A
用内毒素（大肠杆菌）培养的小鼠腹膜渗出细胞培养的条件培养基中含有一种介质，可显著抑制（b> 90%）脂蛋白脂肪酶（三酰基甘油蛋白酰基水解酶，EC 3.1.1.34）分化3T3-L1小鼠前脂肪细胞的活性。这种效果取决于介质的量，并且早在将含有介质的培养基添加到3T3-L1细胞培养后30分钟就很明显。内毒素和未暴露于内毒素的渗出细胞培养的条件培养基均未显示介质的存在。渗出细胞的裂解物也不能抑制脂肪酶的活性。增加胰岛素的量并不能逆转这种抑制，即使是标准实验浓度的1000倍。在内毒素处理的渗出细胞的条件培养基中存在的脂蛋白脂肪酶抑制介质是热不稳定的，其表观MW至少为12,000。该介质不直接抑制脂蛋白脂肪酶活性，也不影响酶活性在培养基中释放的半衰期。显然，内毒素促进渗出细胞释放一种介质，抑制3T3-L1前脂肪细胞中脂蛋白脂肪酶的活性。
Conditioned medium from cultures of mouse peritoneal exudate cells incubated with endotoxin (Escherichia coli) contains a mediator that markedly suppresses (> 90%) lipoprotein lipase (triacylglycero-protein acylhydrolase, EC 3.1.1.34) activity in differentiating 3T3-L1 mouse preadipocytes. The effect is dependent upon the amount of mediator and is evident as early as 30 min after the addition of the mediator-containing medium to 3T3-L1 cell cultures. Neither endotoxin nor conditioned medium from cultures of exudate cells not exposed to endotoxin shows the presence of the mediator. Lysates of the exudate cells are also unable to suppress the lipase activity. Increasing the amount of insulin does not reverse this suppression, even at 1000 times the concentration used for standard experiments. The lipoprotein lipase suppression mediator present in the conditioned medium of endotoxin-treated exudate cells is heat labile and has an apparent MW of at least 12,000. The mediator does not inhibit lipoprotein lipase activity directly nor does it affect the half-life of enzyme activity released in the medium. Evidently, endotoxin promotes the release of a mediator from exudate cells that suppresses the activity of lipoprotein lipase in 3T3-L1 preadipocytes.