Expression of pancreatic secretory trypsin inhibitor: After surgical stress and its' significance.

胰腺分泌型胰蛋白酶抑制剂（PSTI）由Kazal等在1948年首次分离。从那时起，PSTI被认为仅存在于胰腺中，并且是一种特异性胰蛋白酶抑制剂，其防止胰腺和胰液中胰蛋白酶原的自激活。在本项目中，我们证明了血清中的PSTI是一种急性期反应物，并且在手术应激或侵袭时显着增加。升高的幅度远远大于先前已知的急性期反应物。各种恶性肿瘤患者血清PSTI也升高。晚期或转移性恶性肿瘤患者血清PSTI升高的发生率和幅度更大。免疫过氧化物酶染色发现，超过1/3的肿瘤组织中含有PSTI免疫反应阳性细胞，人PSTI mRNA与小鼠表皮生长因子（EGF）mRNA的核苷酸序列高度同源。人PSTI刺激人成纤维细胞中的DNA合成。此外，我们发现，PSTI结合特异性的各种培养的细胞，PSTI的结合位点是不同的EGF受体。这些结果表明，血清中PSTI增加的生理作用与宿主防御组织破坏的生长刺激有关。

Pancreatic secretory trypsin inhibitor (PSTI) was first isolated by Kazal et al. in 1948. Since then PSTI has been thought to exist only in the pancreas and to be a specific trypsin inhibitor that prevents autoactivation of trypsinogen in the pancreas and pancreatic juice. In the present project, we demonstrated that PSTI in serum is an acute phase reactant and that it increases remarkably in response to surgical stress or invasion. The magnitude of the elevation is far greater than those of acute phase reactants previously known. Serum PSTI was also elevated in patients with various malignancies. The incidence and the magnitude of the elevation of serum PSTI were far greater in patients with advanced or metastasized malignancies. By immunoperoxidase staining, we found that more than one-third of various cancer tissues contained PSTI-immunoreactive cells.The nucleotide sequences of human PSTI mRNA and mouse epidermal growth factor (EGF) mRNA were highly homologous. Human PSTI stimulated DNA synthesis in human fibroblasts. Moreover, we revealed that PSTI bound specifically to various cultured cells, and that the binding site for PSTI was distinct from the receptor for EGF. these results suggested that the physiological role of increased PSTI in serum is related to growth stimulation for host defence against tissue destruction.