Hwang D L, Lev-Ran A, Yen C F, Sniecinski I
Department of Diabetes, Endocrinology and Metabolism, City of Hope National Medical Center, Duarte, CA 91010.
Regul Pept. 1992 Jan 23;37(2):95-100. doi: 10.1016/0167-0115(92)90658-h.
Platelet-rich plasma in acidic-citrate-dextrose anticoagulant was kept for 5 days in an oxygen-permeable bag at 22 degrees C in an incubator/rotator. Platelet count remained stable throughout the experiment. On days 0, 3 and 5, aliquots were removed; platelets were isolated by centrifugation at 22 degrees C, 1500 g for 20 min, reconstituted to the original volume with PBS buffer, and the contents of alpha-granules were released by repeated freezing and thawing. Epidermal growth factor (EGF) and beta-thromboglobulin (beta-TG) in the platelet-poor plasma and platelet lysates were determined by radioimmunoassays. Results indicated that in platelet-free plasma, both total EGF and beta-TG increased 3-5-fold after 5 days; this amount represented 10-20% of the factors stored in the platelets. Correspondingly, the EGF and beta-TG contents of the platelet lysates exhibited accompanying decreases. HPLC fractionation showed that the main EGF fraction which progressively decreased in the lysates and increased in plasma had a molecular mass of 140 kDa. The contents of the 67 kDa and 6 kDa fractions did not change substantially. We conclude that under these conditions, the 140 kDa fraction was released preferentially. In view of these and previous experiments, it seems likely that different organs contribute to plasma EGF fractions.
将富含血小板的血浆置于酸性枸橼酸盐葡萄糖抗凝剂中，在培养箱/旋转器中于22℃的透氧袋中保存5天。在整个实验过程中血小板计数保持稳定。在第0、3和5天，取出等分试样；在22℃、1500g条件下离心20分钟分离血小板，用PBS缓冲液将其重悬至原始体积，通过反复冻融释放α-颗粒的内容物。通过放射免疫测定法测定血小板贫浆和血小板裂解物中的表皮生长因子（EGF）和β-血小板球蛋白（β-TG）。结果表明，在无血小板血浆中，5天后总EGF和β-TG均增加了3至5倍；该量占储存在血小板中因子的10%至20%。相应地，血小板裂解物中的EGF和β-TG含量随之降低。高效液相色谱分离显示，在裂解物中逐渐减少而在血浆中增加的主要EGF组分的分子量为140kDa。67kDa和6kDa组分的含量没有实质性变化。我们得出结论，在这些条件下，140kDa组分优先释放。鉴于这些以及之前的实验，不同器官似乎可能对血浆EGF组分有贡献。
