Russell W E, McGowan J A, Bucher N L
J Cell Physiol. 1984 May;119(2):193-7. doi: 10.1002/jcp.1041190208.
In an accompanying communication we demonstrated that about half of the potency of rat serum to stimulate DNA synthesis in cultured adult rat hepatocytes resides in a polypeptidelike substance from the platelets. A lysate of rat platelets was able to restore the potency of platelet-poor rat serum, whereas a lysate of human platelets inhibited thymidine incorporation by the hepatocytes. Moreover, addition to these cultures of either highly purified human platelet-derived growth factor (PDGF) or human platelet factor 4 (PF-4) failed to influence DNA synthesis either alone or in the presence of rat or human platelet-poor serum, which is required for expression of PDGF activity. Unlike the human platelet factors, rat platelet lysate (RPL) was moderately active by itself and was augmented equally well by platelet-poor serum from either source. At concentrations below 5%, platelet-poor serum from hypophysectomized rats was as potent as that from normal rats in augmenting RPL activity. This suggests that, unlike PDGF, which is not activated by hypophysectomized rat serum, the hepatotrophic component of RPL does not require the presence of exogenous somatomedins for activity, but interacts instead with other plasma constituents or with somatomedins produced by the hepatocytes in vitro. Rat platelets do, however, appear to contain PDGF or its rat equivalent in addition to the hepatocyte growth factor, since if they are heated to 100 degrees C for 10 min, their ability to stimulate nuclear labeling in confluent BALB/c 3T3 cells is not impaired, while their ability to stimulate DNA synthesis in rat hepatocytes is destroyed. These studies indicate that the hepatocyte growth factor from rat platelets differs from PDGF in its biological as well as physical characteristics, but that rat platelets also contain PDGF or an equivalent substance.
在一篇随附的通讯文章中，我们证明了大鼠血清刺激成年大鼠培养肝细胞中DNA合成的能力约有一半存在于来自血小板的一种类多肽物质中。大鼠血小板裂解物能够恢复贫血小板大鼠血清的活性，而人血小板裂解物则抑制肝细胞的胸苷掺入。此外，向这些培养物中添加高度纯化的人血小板衍生生长因子（PDGF）或人血小板因子4（PF - 4），无论是单独添加还是在存在大鼠或人贫血小板血清（这是PDGF活性表达所必需的）的情况下，都未能影响DNA合成。与人类血小板因子不同，大鼠血小板裂解物（RPL）本身具有中等活性，并且来自任何一种来源的贫血小板血清都能同样有效地增强其活性。在浓度低于5%时，垂体切除大鼠的贫血小板血清在增强RPL活性方面与正常大鼠的一样有效。这表明，与未被垂体切除大鼠血清激活的PDGF不同，RPL的肝细胞营养成分的活性不需要外源性生长调节素的存在，而是与其他血浆成分或与体外肝细胞产生的生长调节素相互作用。然而，大鼠血小板除了肝细胞生长因子外，似乎还含有PDGF或其大鼠等效物，因为如果将它们加热到100摄氏度10分钟，它们刺激汇合的BALB/c 3T3细胞中核标记的能力不受损害，而它们刺激大鼠肝细胞中DNA合成的能力则被破坏。这些研究表明，大鼠血小板中的肝细胞生长因子在生物学和物理特性上与PDGF不同，但大鼠血小板也含有PDGF或等效物质。
