Voorschuur A H, Kuiper J, Van Noort W L, Van Berkel T J
Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Sylvius Laboratories, The Netherlands.
Biochim Biophys Acta. 1995 Aug 3;1257(3):288-92. doi: 10.1016/0005-2760(95)96845-x.
Periportal and perivenous rat liver parenchymal cells were isolated according to the digitonin-collagenase perfusion method. Affinities and maximal specific binding of a conjugate of glutathione S-transferase and the alpha 2-macroglobulin receptor-associated protein (GST-39kDaP), of lactoferrin and of transferrin to freshly isolated periportal parenchymal cells in vitro were not significantly different from values obtained with perivenous cells. It is concluded that the receptors for these three ligands show a zonally homogeneous expression in rat liver. The zonal homogeneity in binding observed for GST-39kDaP is at variance with the 1.5-fold higher periportal over perivenous binding of trypsin-activated alpha 2-macroglobulin. Since GST-39kDaP as well as trypsin-activated alpha 2-macroglobulin are ligands for the alpha 2-macroglobulin receptor/low-density lipoprotein receptor-related protein, it is suggested that GST-39kDaP can bind to (an) additional receptor(s) with a higher perivenous expression. The zonal homogeneity observed with lactoferrin, an inhibitor of ligand binding to the lipoprotein remnant receptor, may indicate zonal homogeneity of the lipoprotein remnant receptor. The observed zonal homogeneity of the transferrin receptor suggests an equal and essential need for iron by parenchymal cells across the rat liver acinus in vivo.
采用洋地黄皂苷 - 胶原酶灌注法分离大鼠肝门周和肝静脉周围的实质细胞。谷胱甘肽S - 转移酶与α2 - 巨球蛋白受体相关蛋白（GST - 39kDaP）的结合物、乳铁蛋白和转铁蛋白与新鲜分离的体外肝门周实质细胞的亲和力及最大特异性结合，与肝静脉周围细胞所获值无显著差异。结论是，这三种配体的受体在大鼠肝脏中呈区域均一性表达。观察到的GST - 39kDaP结合的区域均一性与胰蛋白酶激活的α2 - 巨球蛋白在肝门周的结合比肝静脉周围高1.5倍的情况不同。由于GST - 39kDaP以及胰蛋白酶激活的α2 - 巨球蛋白都是α2 - 巨球蛋白受体/低密度脂蛋白受体相关蛋白的配体，提示GST - 39kDaP可与肝静脉周围表达较高的其他受体结合。乳铁蛋白是配体与脂蛋白残粒受体结合的抑制剂，观察到的其结合的区域均一性可能表明脂蛋白残粒受体的区域均一性。观察到的转铁蛋白受体的区域均一性表明，在体内大鼠肝腺泡中，实质细胞对铁的需求是均等且必需的。
