Figure 9. Effects of phlorizin on sugar-induced oocyte swelling.

An hSGLT1-expressing oocyte was exposed to 5 mmα-MDG under voltage-clamped and isosmotic conditions (−90 mV). This gave an I_C of about 380 nA and, after about 320 s, a constant rate of volume increase of 14 pl s⁻¹. At 325 s 100 μm phlorizin was added. This reduced the rate of swelling to 5.6 pl s⁻¹ and abolished I_C with a constant of about 5 s. The experiment was simulated by the model of the Appendix (thin line) using the measured values for CR of 244, and of an L_p of 0.59 before phlorizin application and 0.42 after phlorizin application (units, cm s⁻¹(osmol l⁻¹)⁻¹). r was 0.063 cm, V_F/V_T 0.4, and D_i 0.5 × 10⁻⁵ cm² s⁻¹.