Sepúlveda F V, Pearson J D
J Cell Physiol. 1985 Apr;123(1):144-50. doi: 10.1002/jcp.1041230121.
LLC-PK1 and MDCK cells take up cationic amino acids (lysine and arginine) by a specific sodium independent transport system. Uptake is inhibited by ornithine in LLC-PK1 and MDCK cells either in the presence or absence of sodium and by glutamine or homoserine in MDCK cells in the presence of sodium. Trans-stimulation of uptake occurs in the presence of intracellular cationic amino acids. Experiments with valinomycin or with different extracellular potassium concentrations suggest that uptake is dependent on the membrane potential of these cells. These transport features are similar to those previously ascribed to a transport system denominated y+ in other cells. Further experiments suggested that this carrier system is localised to the basolateral membrane in each cell type.
LLC-PK1细胞和MDCK细胞通过一种特定的不依赖钠的转运系统摄取阳离子氨基酸（赖氨酸和精氨酸）。在LLC-PK1细胞和MDCK细胞中，无论有无钠，鸟氨酸均可抑制摄取；在有钠存在的情况下，MDCK细胞中的谷氨酰胺或高丝氨酸也可抑制摄取。在细胞内存在阳离子氨基酸的情况下会发生摄取的反式刺激。用缬氨霉素或不同细胞外钾浓度进行的实验表明，摄取依赖于这些细胞的膜电位。这些转运特征与先前在其他细胞中归因于一种称为y+的转运系统的特征相似。进一步的实验表明，这种载体系统定位于每种细胞类型的基底外侧膜。
