Cowin A J, Davis J R, Bidey S P
Department of Medicine, University of Manchester, U.K.
J Mol Endocrinol. 1992 Dec;9(3):197-205. doi: 10.1677/jme.0.0090197.
The present studies have demonstrated the production of transforming growth factor-beta 1 (TGF-beta 1) by porcine thyroid follicular cells (TFCs) maintained in vitro as subconfluent monolayers, and have confirmed a stimulatory effect of iodide on thyroidal TGF-beta 1 mRNA and peptide release. RNA extracted from TFCs maintained in the absence of iodide contained a 2.5 kb transcript which hybridized specifically with a cDNA probe for human TGF-beta 1, and which showed an approximate doubling in intensity in cells exposed to 10 mumol NaI/1. In the presence of the anti-thyroid thionamide drug methimazole (MMI; 1 mmol/l), the action of iodide on TGF-beta 1 mRNA was attenuated, although MMI alone had no effect on the control level of TGF-beta 1 mRNA. The TGF-beta 1 peptide content of TFC-conditioned media (TFC-CM) was assessed using the fetal mink lung cell line Mv1Lu, in which activated TGF-beta 1 specifically suppresses trichloroacetic acid-precipitable [methyl-3H]thymidine incorporation. Newly conditioned TFC-CM stimulated [methyl-3H]thymidine incorporation into Mv1Lu cells, but after heat treatment to inactivate growth stimulators and activate the latent TGF-beta 1 component this medium inhibited [methyl-3H]thymidine incorporation. This inhibitory effect was prevented by immunoadsorption of TFC-CM with a TGF-beta 1-neutralizing antiserum, confirming the specificity of the inhibitory response. The inhibitory activity of TFC-CM was increased when the TFCs were preincubated with 10 mumol NaI/1, and lost when TFCs were exposed to MMI. In conclusion, TFCs produce TGF-beta 1 mRNA and TGF-beta 1 peptide, which are both increased by iodide treatment in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
目前的研究表明，体外维持为亚汇合单层的猪甲状腺滤泡细胞（TFCs）可产生转化生长因子β1（TGF-β1），并证实了碘化物对甲状腺TGF-β1 mRNA和肽释放具有刺激作用。从无碘条件下培养的TFCs中提取的RNA含有一个2.5 kb的转录本，该转录本与人TGF-β1的cDNA探针特异性杂交，并且在暴露于10 μmol NaI/1的细胞中强度约增加一倍。在抗甲状腺硫代酰胺药物甲巯咪唑（MMI；1 mmol/l）存在的情况下，碘化物对TGF-β1 mRNA的作用减弱，尽管单独的MMI对TGF-β1 mRNA的对照水平没有影响。使用胎儿水貂肺细胞系Mv1Lu评估TFC条件培养基（TFC-CM）中的TGF-β1肽含量，在该细胞系中，活化的TGF-β1特异性抑制三氯乙酸可沉淀的[甲基-3H]胸苷掺入。新制备的TFC-CM刺激[甲基-3H]胸苷掺入Mv1Lu细胞，但经过热处理以灭活生长刺激剂并激活潜伏的TGF-β1成分后，该培养基抑制[甲基-3H]胸苷掺入。用TGF-β1中和抗血清对TFC-CM进行免疫吸附可防止这种抑制作用，证实了抑制反应的特异性。当TFCs与10 μmol NaI/1预孵育时，TFC-CM的抑制活性增加，而当TFCs暴露于MMI时，抑制活性丧失。总之，TFCs产生TGF-β1 mRNA和TGF-β1肽，体外碘化物处理均可使其增加。（摘要截短于250字）
