Stimulation by GH of IGF1 proforms synthesized by rabbit chondrocytes cultured with bFGF in serum-free medium.
Stimulation by GH of IGF1 proforms synthesized by rabbit chondrocytes cultured with bFGF in serum-free medium.
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GH 刺激与 bFGF 在无血清培养基中培养的兔软骨细胞合成的 IGF1 原型。
DOI：
10.1016/0014-4827(92)90094-o
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发表时间：
1992
影响因子：
3.7
通讯作者：
Corvol,MT
中科院分区：
文献类型：
--
作者：
Demarquay,D;Dumontier,MF;Bourguignon,J;Hintz,RL;Corvol,MT
分析无血清培养的兔骺软骨细胞产生IR-IGF 1的情况。通过加入10 ng/ ml碱性成纤维细胞生长因子（bFGF）而不加入或加入100 ng/ml重组人生长激素（hGH）来诱导细胞增殖。单独GH不诱导细胞增殖。单独用bFGF处理的软骨细胞分泌与细胞的有丝分裂活性成比例的IR-IGF 1活性。一个特定的阳性IGF 1免疫染色定位在高尔基体的控制和生长激素处理的细胞。回收到培养基中的IR-IGF 1活性主要由表观MW 6-8 kDa、9-14 kDa和16-18 kDa的三个部分组成。[35 S]甲硫氨酸脉冲追踪实验表明，放射性标记的16-18 kDa IR-IGF 1部分转化为9-14 kDa和6-8 kDa部分。在平衡时，70%的软骨细胞IR-IGF 1活性以9- 18-kDa形式回收，其含有高IR-proIGF 1A活性。6-8 kDa组分具有与成熟IGF 1肽相似的生化特征。当向培养物中加入4%胎牛血清时，观察到类似的结果。添加100 ng/ml hGH显著且特异性增加IGF 1前体物质，因此其占总IR-IGF 1活性的90%。在培养的第16天，当细胞停止分裂时，软骨细胞IR-IGF 1的量显著低于细胞增殖期间，hGH对这种产生没有影响。这些数据表明，培养的软骨细胞产生更多的IGF 1前体比成熟的IGF 1和生长激素特异性刺激IGF 1前体的生物合成，但不是IGF 1本身。软骨细胞中IGF 1预制体的GH依赖性生物学功能仍有待证实。
The IR-IGF1 production by rabbit epiphyseal chondrocytes cultured in serum-free medium was analyzed. Cell proliferation was induced by the addition of 10 ng/ ml basic fibroblast growth factor (bFGF) without or with 100 ng/ml recombinant human growth hormone (hGH). GH alone induced no cell multiplication. Chondrocytes treated with bFGF alone secreted an IR-IGF1 activity proportional to the mitotic activity of the cells. A specific positive IGF1 immunostaining was localized in the Golgi of control and hGH-treated cells. The IR-IGF1 activity recovered into culture medium was mainly composed of three fractions of apparent MW 6-8 kDa, 9–14 kDa, and 16–18 kDa. [35S]Methionine pulse-chase experiments indicated that the radiolabeled 16–18 kDa IR-IGF1 fraction was partly converted into the 9–14 kDa and 6–8 kDa fractions. At equilibrium, 70% of the chondrocyte IR-IGF1 activity was recovered as 9- to 18-kDa forms which contained high IR-proIGF1A activity. The 6–8 kDa fraction had biochemical characteristics similar to those of the mature IGF1 peptide. Similar results were observed when 4% fetal calf serum was added to the culture. The addition of 100 ng/ml of hGH significantly and specifically increased IGF1 precursor material, which thus represented 90% of total IR-IGF1 activity. On Day 16 of the culture, when cells stopped dividing, the amount of chondrocyte IR-IGF1 was significantly lower than during cell proliferation, and hGH had no effect on this production. These data indicate that cultured chondrocytes produce more IGF1 precursors than mature IGF1 and that GH specifically stimulates biosynthesis of IGF1 precursors but not IGF1 per se. A GH-dependent biological function of IGF 1 preforms in chondrocytes remains to be demonstrated.