Fig. 3. Analysis of urea uptake in Xenopus oocytes injected with turtle UT cRNA or water. Summary of [¹⁴C]urea accumulated over a 10 min period by water-injected control oocytes or oocytes expressing turtle UT. Oocytes injected with turtle UT cRNA showed significant increases in urea uptake compared with the water-injected control oocytes; phloretin significantly inhibited turtle UT-mediated urea influx. Open bar represents urea uptake in the water-injected oocyte group after incubation in Barth's medium for 10 min. Filled bars show uptake after incubation in the solution with or without 0.5 mmol l^–1 phloretin for 10 min. Values are presented as means ± s.e.m. of six oocytes in each group. ^**P<0.01 versus control or UT with phloretin treatment (ANOVA followed by Bonferroni's test).