Cornelius P, Enerback S, Bjursell G, Olivecrona T, Pekala P H
Department of Biochemistry, East Carolina University School of Medicine, Greenville, NC 27858.
Biochem J. 1988 Feb 1;249(3):765-9. doi: 10.1042/bj2490765.
Tumour necrosis factor (TNF) was previously shown to suppress lipoprotein lipase (LPL) synthesis and activity in 3T3-L1 adipocytes. The present study examined the effect of TNF on amounts of mRNA for LPL in 3T3-L1 cells. Northern-blot analysis of polyadenylated RNA using a cDNA probe to guinea-pig LPL identified two predominant species of LPL message, 3.7 and 3.9 kilobases in size. The steady-state amounts of these mRNAs increased 10-fold upon expression of the adipocyte phenotype. A single dose of 1.5 nM-TNF decreased LPL mRNA by approx. 60% in 17 h with a corresponding decrease in LPL activity, an effect that was reversed 48 h after exposure to TNF. The results demonstrate that TNF reversibly down-regulates LPL mRNA in fully differentiated 3T3-L1 adipocytes. Cells induced to differentiate in the presence of 1.5 nM-TNF exhibited a delayed time course for development of the adipocyte phenotype, as judged by attenuation of the normal increase in LPL mRNA that occurs with differentiation.
肿瘤坏死因子（TNF）先前已被证明可抑制3T3-L1脂肪细胞中脂蛋白脂肪酶（LPL）的合成及活性。本研究检测了TNF对3T3-L1细胞中LPL mRNA含量的影响。使用豚鼠LPL的cDNA探针对聚腺苷酸化RNA进行Northern印迹分析，鉴定出两种主要的LPL信使RNA，大小分别为3.7和3.9千碱基。这些mRNA的稳态含量在脂肪细胞表型表达时增加了10倍。单剂量1.5 nM - TNF在17小时内使LPL mRNA减少约60%，同时LPL活性相应降低，该效应在接触TNF 48小时后逆转。结果表明，TNF可在完全分化的3T3-L1脂肪细胞中可逆性下调LPL mRNA。在1.5 nM - TNF存在下诱导分化的细胞，根据分化时LPL mRNA正常增加的减弱情况判断，其脂肪细胞表型的发育呈现延迟的时间进程。
