Fig. 4.

Intra-oocyte glutamate injection trans-stimulates estrone sulphate uptake in oocytes expressing OATP2A1 despite the fact that glutamate does not appear to be an OATP2A1 substrate. Compared to ³H-ES uptake alone in OATP2A1 oocytes, uptake was inhibited by cold ES, but not by glutamate. The injection of 5 mM glutamate into OATP2A1 expressing oocytes resulted in a trans-stimulation of ³H-ES uptake (p = 0.006). Data are analysed by two-way ANOVA and presented as mean and SEM and adjusted for water injected responses (n = 3 individual ovaries, 5 oocytes per condition).