Figure 2.

Kinetics of (A) hOCT2-, (B) mOct2-mediated ¹⁴C-metformin transport and (C) hOCT2-, (D) mOct2-mediated ³H-MPP transport. Human and mouse transfected HEK293 cells were incubated for 1 min at 37 °C in the presence of ³H-labeled (2 nM) and increasing concentrations of unlabeled MPP or 2 min in the presence of ¹⁴C-labeled (1 µM) and increasing concentrations of unlabeled metformin. Transporter specific net uptake was fit to the Michaelis–Menten equation to obtain the affinity constant K_m and maximum transport velocity V_max by non-linear regression analysis using Sigma Plot 13.0 software. Each data point represents the mean of two independent experiments carried out in triplicate ± average deviation.