Figure 7. Demonstration of PAT1-mediated amino acid efflux.

(A) Individual oocytes were injected with 5 nmol of L-proline (including 1pmol of L-[³H]proline as a tracer) and efflux was measured in the absence (□) or the presence of 20 mM glycine (■) or alanine (●) in the incubation medium. Efflux of L-[³H]proline from water-injected control oocytes is also shown (○). (B) PAT1-mediated efflux of proline from preloaded oocytes (injection of 5 nmol of L-proline, including 1 pmol of L-[³H]proline per oocyte) as a function of increasing concentrations of glycine (1–20 mM) in the incubation buffer. Efflux rates of labelled L-proline were determined after 10 min of incubation under the various conditions and represent the means±S.E.M. for at least eight oocytes per variable.