FIGURE 2.
Effect of DTT on hPAT1 function. A, oocytes injected either with water (control) or hPAT1 cRNA (hPAT1) were incubated for 20 min at room temperature in Barth's medium with and without 10 mm DTT. The currents induced by 20 mm glycine at pH 6.5 were determined in the absence and presence (10 mm) of DTT. Currents (I20Gly) were calculated as the difference of the currents measured in the presence and absence of glycine (n = 6 oocytes). B, HRPE cells transfected with empty vector pSPORT1 (control) or pSPORT1-hPAT1 (hPAT1) were treated with 10 mm DTT for 20 min at room temperature. Uptake of l-[3H]proline (20 nm) was measured in the absence or presence (10 mm) of DTT at pH 6.0 for 10 min. Data are means ± S.E., n = 4.