fig4

Figure 4. Reabsorption of β₂M and albumin by the PTCs. In normal kidney health, nearly all β₂M is internalized into PTCs via endocytosis, mediated by the megalin/cubilin receptor system, followed by degradation^[120,121]. Albumin is also reabsorbed through the same endocytosis mechanism, fluid-phase endocytosis, and is returned to the bloodstream via transcytosis^[122-124]. Cd intoxication disrupted the endocytosis mechanism, thereby increasing the excretion of both β₂M and albumin^[125]. PTC: Proximal tubular epithelial cell; β₂M: β₂-microglobulin; Cd: cadmium.