Lithium blockade of the inhibitory effect of high albumin concentration on albumin endocytosis in PT cells measured by cell-associated fluorescence.

LLC-PK1 cells were grown in 24-well plates until 95% confluence was reached. Then, the cells were incubated with albumin and/or lithium under different experimental conditions. Albumin endocytosis measured by cell-associated fluorescence using albumin-FITC. A) Dose-response effect of lithium on albumin endocytosis (n = 9). The lithium concentrations used were 0.1, 1, 5,10, and 20 mM. B) Time-course effect of lithium on albumin endocytosis (n = 4). Times of incubation were 0, 2, 4, 6, and 12 h. C) Lithium treatment reversed the inhibitory effect of high albumin concentration on albumin endocytosis (n = 7). The cells were pre-incubated with 20 mg/mL albumin in the absence or presence of increasing lithium concentrations (5, 10, and 20 mM). The results are expressed as means ± SE. A) *P < 0.05 versus control (in the absence of lithium), #P < 0.05 versus 1 mM lithium; &P < 0.05 versus 10 mM lithium. B) *P < 0.05 versus control (in the absence of lithium). C) *P < 0.05 versus control (in the absence of albumin), #P < 0.05 versus albumin.