Fig. 2

Uptake of [³H]serotonin and [¹²⁵I]MIBG in SERT- and NET-transfected HEK293 cells. a, b Results of Western blotting analysis on samples of transfected HEK cells. a Primary antibody against human SERT. b Primary antibody against human NET. c Uptake of [³H]serotonin by HEK-SERT cells. d Uptake of [¹²⁵I]MIBG by HEK-SERT cells. e Uptake of [¹²⁵I]MIBG by HEK-NET cells. Closed symbols (■, ●, ▲) represent baseline-corrected, transporter-specific uptake. Open symbols (□, ○, Δ) represent non-specific cellular uptake observed in HEK-Mock cells. Cells were incubated with substrate for 1 h. The Michaelis-Menten graph is depicted as a black dashed line. f The kinetic parameters from this analysis: V_max in μmol/mg protein/min; K_m in μM; catalytic efficiency: ratio \( \frac{V_{\mathrm{max}}}{K_m} \). Data represent mean ± SD (n = 2)