Fig. 1. The follicle sets oocyte pH_i during growth. (A) An example of one experiment in which follicle-enclosed and denuded oocytes were microinjected with SNARF-dex to determine pH_i. Brightfield (left) and fluorescence (right) images are shown. Note that fluorescence is restricted to the oocyte. Scale bar 50 µm. (B) Oocytes within each experiment were grouped in 5 µm increments. pH_i increased significantly with increasing size in denuded oocytes (P<0.0001), whereas there is no significant difference in pH_i between size groupings in follicle-enclosed oocytes (P>0.25). Each point comprises between four and 17 oocytes from two to eight replicates.