Steinberg J
Lab Invest. 1978 Nov;39(5):491-6.
The metabolic turnover of collagen in 3T6 fibroblast cultures was studied at various stages of growth by compartmental analysis of hydroxyproline content and of the conversion of radioactive proline to hydroxyproline. Quantitative and radioactive hydroxyproline measurements were directly parallel, although the latter method was more sensitive in demonstrating collagen synthesis in all phases of growth. Hydroxyproline formation as an index of collagen synthesis was abruptly accelerated at the time of confluence, and was well maintained at the new rate despite a gradual decline in the rate of general protein synthesis. Ethanol fractionation of growth medium proved superior to perchloric acid extraction in providing a pool of soluble hydroxyproline clearly derived from collagen degradation. Breakdown products were released at a constant rate per cell in all growth phases and accumulated to high levels in continuous culture. The fractional rate of collagen breakdown (percentage of hydroxyproline radioactivity) was highest in early logarithmic growth. Its gradual decline as cultures aged reflected the increased hydroxyproline content and improved stability of collagen under these conditions.
通过对羟脯氨酸含量以及放射性脯氨酸向羟脯氨酸转化的区室分析，研究了3T6成纤维细胞培养物中胶原蛋白在不同生长阶段的代谢周转情况。定量和放射性羟脯氨酸测量结果直接平行，尽管后一种方法在证明生长各阶段的胶原蛋白合成方面更敏感。作为胶原蛋白合成指标的羟脯氨酸形成在汇合时突然加速，并且尽管总蛋白合成速率逐渐下降，但仍以新的速率良好维持。在提供明显源自胶原蛋白降解的可溶性羟脯氨酸库方面，生长培养基的乙醇分级分离被证明优于高氯酸提取。在所有生长阶段，分解产物以每个细胞恒定的速率释放，并在连续培养中积累到高水平。胶原蛋白分解的分数速率（羟脯氨酸放射性的百分比）在对数生长早期最高。随着培养物老化，其逐渐下降反映了在这些条件下羟脯氨酸含量的增加和胶原蛋白稳定性的提高。
