Bar R S, Clemmons D R, Boes M, Busby W H, Booth B A, Dake B L, Sandra A
Department of Internal Medicine, Veterans Administration Hospital, University of Iowa, Iowa City 52246.
Endocrinology. 1990 Sep;127(3):1078-86. doi: 10.1210/endo-127-3-1078.
Insulin-like growth factor (IGF) binding proteins (IGFBP) were purified from conditioned media of cultured bovine endothelial cells (ECBP) and from human amniotic fluid (IGFBP-1), and then labeled by radioiodination. 125I-ECBP and 125I-IGFBP-1 were perfused through isolated beating rat hearts for 1 and 5 min, and the hearts fixed and analyzed for 125I-BP content and distribution. One to 4% of the perfused 125I-ECBP and 125I-IGFBP-1 crossed the capillary boundary. The ECBPs predominantly localized as intact 125I-BP in connective tissue elements of the heart with less 125I-BP in cardiac muscle. The ratio of 125I-ECBP in connective tissue: muscle (normalized to percent vol of these compartments) was greater than or equal to 10:1. In contrast, the IGFBP-1 had a greater affinity for cardiac muscle with ratios of 125I-IGFBP-1 in connective tissue:muscle of approximately 1:2. When 125I-IGF-I, in the absence of any BPs, was perfused through the hearts approximately 3-5% left the microcirculation and was found in subendothelial tissues. 125I-IGF-I localized primarily to cardiac muscle with a distribution of connective tissue:cardiac muscle of about 1:3. The findings in the isolated perfused heart were confirmed in intact animals. After 125I-IGFBP-1 was injected into anesthetized rats and allowed to circulate for 5 min, substantial radioactivity was associated with the heart. As in the isolated heart, the IGFBP-1 preferentially localized to cardiac muscle with a connective tissue:cardiac muscle ratio of 1:3. We conclude that IGFBPs produced by endothelial cells and the IGFBP-1 contained in amniotic fluid can cross the capillary boundaries of the rat heart, and that the ECBPs preferentially localize in connective tissue elements of the myocardium, whereas IGFBP-1 predominantly localizes in cardiac muscle.
胰岛素样生长因子（IGF）结合蛋白（IGFBP）从培养的牛内皮细胞条件培养基（ECBP）和人羊水（IGFBP - 1）中纯化出来，然后通过放射性碘化进行标记。将125I - ECBP和125I - IGFBP - 1灌注到离体搏动的大鼠心脏中1分钟和5分钟，然后固定心脏并分析125I - BP的含量和分布。灌注的125I - ECBP和125I - IGFBP - 1中有1%至4%穿过毛细血管边界。ECBP主要以完整的125I - BP形式定位在心脏的结缔组织成分中，心肌中的125I - BP较少。结缔组织中125I - ECBP与肌肉中的比例（根据这些腔室的体积百分比进行归一化）大于或等于10:1。相比之下，IGFBP - 1对心肌的亲和力更高，结缔组织中125I - IGFBP - 1与肌肉中的比例约为1:2。当在没有任何BP的情况下将125I - IGF - I灌注通过心脏时，约3% - 5%离开微循环并存在于内皮下组织中。125I - IGF - I主要定位在心肌中，结缔组织与心肌的分布比例约为1:3。在完整动物中证实了离体灌注心脏中的这些发现。将125I - IGFBP - 1注射到麻醉大鼠体内并使其循环5分钟后，心脏有大量放射性物质。与在离体心脏中一样，IGFBP - 1优先定位在心肌中，结缔组织与心肌的比例为1:3。我们得出结论，内皮细胞产生的IGFBP和羊水中所含的IGFBP - 1可以穿过大鼠心脏的毛细血管边界，并且ECBP优先定位在心肌的结缔组织成分中，而IGFBP - 1主要定位在心肌中。
