Ultrastructural and immunohistochemical studies on endocytic pathway of high density lipoprotein (HDL) in cells.

我们用组织化学、免疫组织化学、电子显微镜、细胞化学和生物化学等方法研究了高密度脂蛋白在几种细胞中的内吞途径。此外，我们还检测了几个细胞内低密度脂蛋白(LDL)和辣根过氧化物酶(HRP)的内吞途径。用生物素标记大鼠高密度脂蛋白、大鼠低密度脂蛋白、兔高密度脂蛋白和低密度脂蛋白。高密度脂蛋白生物素和低密度脂蛋白生物素最初与肝细胞的相互作用发生在分布在基侧(正弦)质膜上的结合部位。配体的内化涉及包被的粘液、包被的小泡、早期的内小体、晚期的内小体和溶酶体。但高密度脂蛋白生物素和低密度脂蛋白生物素在细胞内膜上的结合部位不同，高胆固醇饲料连续4个月对兔肝细胞和肾上腺皮质细胞高密度脂蛋白生物素内化无抑制作用。

We used histochemistry, immunohistochemistry, electromicroscopy, cytochemistry and biochemistry to investigate the endocytic pathway of high density lipoprotein (HDL) in several cells. In addition, we examined the endocytic pathway of low density lipoprotein (LDL) and horseradish peroxidase (HRP) in several cells.HDL and LDL were isolated from normal rat and rabbit blood by sequential ultracentrifugation. Rat HDL,rat LDL,rabbit HDL and rabbit LDL were labeled with biotin.The initial interaction of HDL-biotin and LDL-biotin with hepatocytes occurred at binding sites distributed over the basolateral (sinusoidal) plasma membrane. Ligand internalization was involved coated puits, coated vesicles, early endosomes, late endosomes, and lysosomes. However, the binding sites distributed over the endocytic membrane were difference between HDL-biotin and LDL-biotin.Internalization of HDL-biotin in hepatocytes and adrenal cortical cells of rabbit was no inhibition by a hypercholesterol diet containing 0.5% cholesterol for 4 months.