Smith R D
Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK.
Biochem Mol Biol Int. 1995 May;35(6):1315-21.
The proliferation of sparse cultures of RIE-1 rat intestinal epithelial cells was potently inhibited by transforming growth factor type beta 1 (TGF-beta 1), with a half-maximal effect at 10-30 pg/ml. As judged by [3H]thymidine incorporation assays, this growth inhibitory action became apparent 4-6 h after addition of TGF-beta 1 to the cells. RIE-1 cells express high-affinity (KD approximately 5.6 pM) receptors for 125I-TGF-beta 1. Affinity cross linking experiments labelled two major species of putative TGF-beta 1 receptors with M(r) values of 235,000 and 65,000. Medium conditioned by confluent cultures of RIE-1 cells contained latent TGF-beta-like activity that was activated at low pH. These findings support a model of autocrine growth inhibition of intestinal crypt cells by TGF-beta.
转化生长因子β1（TGF-β1）可有效抑制RIE-1大鼠肠上皮细胞稀疏培养物的增殖，在10 - 30 pg/ml时产生半数最大效应。通过[3H]胸苷掺入试验判断，在向细胞中添加TGF-β1后4 - 6小时，这种生长抑制作用变得明显。RIE-1细胞表达对125I-TGF-β1的高亲和力（KD约为5.6 pM）受体。亲和交联实验标记了两种主要的假定TGF-β1受体，其分子量分别为235,000和65,000。由RIE-1细胞汇合培养物条件化的培养基含有在低pH下被激活的潜伏性TGF-β样活性。这些发现支持了TGF-β对肠隐窝细胞自分泌生长抑制的模型。
