Hormonal control of immunoreactive somatomedin production by cultured human fibroblasts.
Hormonal control of immunoreactive somatomedin production by cultured human fibroblasts.
复制标题
培养的人成纤维细胞产生免疫反应性生长调节素的激素控制。
DOI：
10.1172/jci110001
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
VanWyk,JJ
中科院分区：
文献类型：
--
作者：
Clemmons,DR;Underwood,LE;VanWyk,JJ
人类生长激素(HGH)被认为是体内生长抑素分泌的有力刺激因素。然而，生长激素诱导生长原子素的体外研究一直很困难，因为还没有鉴定出含有高浓度生长原子素的器官。由于胎鼠外植体已被证明在体外产生生长原子素，我们进行了研究，以确定出生后的人类成纤维细胞单层是否也产生生长原子素，如果是，它的产生是否受其他激素的调节。将静止的人成纤维细胞暴露在无血清的最低基本培养液中，并用生长原子素-C的特异性放射免疫法测定培养液中生长原子素的浓度。随着培养时间的延长，生长抑素逐渐增加，每24小时每105个细胞中的生长抑素含量为0.08U/ml。这是对免疫活性生长激素实际浓度的低估，因为在酸处理后测得的量至少是未处理介质中的四倍。生长激素刺激免疫反应性生长抑素的产生呈剂量依赖性：5 ng hGH/ml=0.1U/ml/105个细胞，50 ng hGH/ml=0.25U/ml/105个细胞。血小板衍生生长因子和成纤维细胞生长因子也有刺激作用，但表皮生长因子、甲状腺素或皮质醇没有作用。暴露于人成纤维细胞的培养基能刺激BALB/c 3T3成纤维细胞(一种不产生生长原子素的细胞)的DNA合成。从Sephacryl S-200中洗脱的中间体免疫反应性生长抑素有两个主要峰(150,000和8,000摩尔重量)。高分子量峰与使用全血清时观察到的峰相似。这些研究为研究控制人体组织合成生长抑素的体液和非体液因素提供了一个模型系统。由于免疫反应性生长抑素的产生可能是成纤维细胞生长的限速因素，因此，对生长抑素产生的激素控制的描述应该有助于更好地理解控制人成纤维细胞生长的机制。
Human growth hormone (hGH) is known to be a potent stimulator of somatomedin secretion in vivo. The induction of somatomedin by growth hormone has been difficult to study in vitro, however, because no organ containing a high concentration of somatomedin has been identified. Because fetal mouse explants have been shown to produce somatomedin in vitro, we have undertaken studies to determine whether postnatal human fibroblast monolayers also produce somatomedin, and if so, whether its production is regulated by other hormones. Quiescent human fibroblasts were exposed to serum-free minimum essential medium, and the medium was assayed for somatomedin concentration using a specific radioimmunoassay for somatomedin-C. A progressive rise in immunoreactive somatomedin to 0.08 U/ml per 105cells per 24 h was observed over 72 h of incubation. This was an underestimation of the actual concentration of immunoreactive somatomedin since the amount measured following acid treatment was at least fourfold higher than in the untreated medium. Growth hormone stimulated immunoreactive somatomedin production in a dose-dependent manner: 5 ng hGH/ml = 0.1 U/ml per 105cells; 50 ng hGH/ml = 0.25 U/ml per 105cells. Platelet-derived growth factor and fibroblast growth factor were also stimulatory, but epidermal growth factor, thyroxine, or cortisol had no effect. Media that had been exposed to human fibroblasts stimulated DNA synthesis in BALB/c 3T3 fibroblasts (a cell type that does not produce somatomedin). Medium-derived immuno-reactive somatomedin eluted from Sephacryl S-200 in two major peaks (150,000 and 8,000 mol wt). The higher molecular weight peak is similar to the one observed when whole serum was used. These studies provide a model system for studying the humoral and nonhumoral factors that control the biosynthesis of somatomedin by human tissues. Since immunoreactive somatomedin production may be a rate-limiting factor for fibroblast growth, the delineation of the hormonal control of somatomedin production should lead to a better understanding of the mechanisms controlling human fibroblast growth.