Fig 3. ¹⁴C-PBT434 accumulation and efflux from hBMVEC.

hBMVEC were loaded with 20 μM ¹⁴C-PBT434 at 37°C for 0.5-3h (A) and the amount of ¹⁴C-PBT434 accumulated in the lysates at each time point was plotted, n = 12 experimental replicates/time point. The rate of ¹⁴C-PBT434 accumulation from 0.5-3h was calculated using linear regression analysis to be 30.1 ± 9.8 pmol/mg/h, reaching an endpoint of 650±51 pmol/mg protein, or approximately 19–24 μM in the cell. For efflux, hBMVEC were loaded with 20 μM ¹⁴C-PBT434 at 37°C for 30min and then incubated in efflux medium at 37°C for 0–2.5h, and the amount of ¹⁴C-PBT434 remaining in lysates at each time point was plotted, n = 3–4 experimental replicates/time point (B). The line is a standard exponential fit to the data. The apparent plateau estimated by this fit is 27±4 pmol/mg protein, or ~0.5–0.6 μM remaining in the cells.