Ash P, Francis M J
J Endocrinol. 1975 Jul;66(1):71-8. doi: 10.1677/joe.0.0660071.
Isolated rat liver, when perfused with medium containing bovine growth homone produced somatomedin-like activity (liver somatomedin). Liver somatomedin is useful in studies of the hormonal control of the cartilage plate in vitro, since unlike serum it is not contaminated with other hormones or growth factors (apart from growth hormone). Chondrocytes isolated from various regions of the growth cartiage responded differently to liver s-omatomedin; proliferative chondrocytes, like those isolated from the articular cartilage, showed increased [3H]thymidine uptake in response to liver somatomedin, whereas hypertrophic chondrocytes did not respond. It is suggested that there is a reduction in the response to somatomedin by growth plate chondrocytes as they pass from the proliferative to the hypertrophic state. Thyroxine, thought to be involved in thr processes of hypertrophy and new bone formation, did not directly affect [3H]thymidine uptake by proliferative chondrocytes, but inhibited stimulation of both their activity by liver somatomedin. Mesurement of [3H]thymidine uptake by isolated articular chondrocytes may provide a useful assay for both liver and serum somatomedin. The graded response of chondrocytes to increasing concentrations of liver somatomedin paralleled the response to increasing levels of serum somatomedin.
将离体大鼠肝脏用含牛生长激素的培养基灌注时，会产生类胰岛素生长因子样活性物质（肝脏类胰岛素生长因子）。肝脏类胰岛素生长因子在体外软骨板激素控制的研究中很有用，因为与血清不同，它不会被其他激素或生长因子（除生长激素外）污染。从生长软骨不同区域分离的软骨细胞对肝脏类胰岛素生长因子的反应不同；增殖性软骨细胞，如从关节软骨分离的那些细胞，对肝脏类胰岛素生长因子有反应，表现为[3H]胸腺嘧啶核苷摄取增加，而肥大性软骨细胞则无反应。提示生长板软骨细胞从增殖状态转变为肥大状态时，对类胰岛素生长因子的反应降低。甲状腺素被认为参与肥大和新骨形成过程，它并不直接影响增殖性软骨细胞对[3H]胸腺嘧啶核苷的摄取，但会抑制肝脏类胰岛素生长因子对其活性的刺激作用。测定分离的关节软骨细胞对[3H]胸腺嘧啶核苷的摄取量，可能为检测肝脏和血清类胰岛素生长因子提供一种有用的方法。软骨细胞对肝脏类胰岛素生长因子浓度增加的分级反应与对血清类胰岛素生长因子水平升高的反应相似。
