The insulin-like growth factors (IGFs) in follicular fluid are predominantly bound in the ternary complex.
The insulin-like growth factors (IGFs) in follicular fluid are predominantly bound in the ternary complex.
复制标题
卵泡液中的胰岛素样生长因子（IGF）主要结合在三元复合物中。
作者：
S. C. Hughes;H. Mason;S. Franks;J. Holly
人卵泡液中IGFs及其相关结合蛋白（IGFBPs）的存在已得到充分证实。此外，已经发现卵泡液中IGF系统的大多数成分在总量或蛋白水解裂解方面有所不同，这取决于卵泡的健康状况。在这项研究中，我们检查了酸不稳定亚基（ALS），发现卵泡液中的水平（平均146 nmol/l）几乎是循环中的50%。该ALS量显著高于其他循环外液体中的ALS量（滑液为20.9 nmol/l，皮肤水疱液为31.4 nmol/l）。在循环中，ALS水平摩尔过量，并没有改变闭锁和优势卵泡。尽管ALS的来源可能是血液（来自卵巢细胞培养物的条件培养基没有可测量的ALS），但似乎这种糖蛋白不仅仅是从循环中扩散，因为毛细血管内皮在优势卵泡中变得更具渗透性，这并没有反映在ALS的水平上。对来自健康和闭锁卵泡的流体中IGF-I、IGF-II和IGFBP-3的分布的分析揭示，这些生长因子中的大多数（>总IGF-II的80%）在150 KDa复合物中，表明存在的ALS是功能性的，因为它与IGFBP-3和IGF的分子形成三元复合物。在分析的任何卵泡液中均未发现游离IGF-II，闭锁卵泡中不饱和IGFBP-3的量也未增加。总之，我们已经表明，卵泡液中测得的大多数IGF，无论是来自健康还是闭锁卵泡，都结合在三元复合物中。
The presence of IGFs and their associated binding proteins (IGFBPs) in human follicular fluid is well documented. Furthermore, most of the constituents of the IGF system in follicular fluid have been found to vary, either in total amount or by proteolytic cleavage, depending on the health status of the follicle. In this study we have examined the acid-labile subunit (ALS) and found that levels in follicular fluid (mean 146 nmol/l) were almost 50% of those in the circulation. This amount of ALS was considerably greater than that found in other extracirculatory fluids (20.9 for synovial fluid and 31.4 nmol/l for skin blister fluid). As in the circulation, ALS levels were in molar excess and did not vary between atretic and dominant follicles. Although the source of ALS is probably from blood (conditioned medium from ovarian cell cultures had no measurable ALS) it would appear that this glycoprotein is not merely diffusing from the circulation as the capillary endothelium becomes more permeable in dominant follicles and this is not reflected in the level of ALS. Analysis of the distribution of IGF-I, IGF-II and IGFBP-3 in fluid from healthy and atretic follicles revealed that the majority of these growth factors (> 80% of total IGF-II) were in the 150KDa complex, indicating that the ALS present was functional, in that it formed the ternary complex with a molecule of IGFBP-3 and IGF. No free IGF-II was found in any of the follicular fluids analysed nor was there any increase in the amount of unsaturated IGFBP-3 in atretic follicles. In summary, we have shown that the majority of IGF measured in follicular fluid, whether from healthy or atretic follicles, is bound in the ternary complex.