Figure 19. (a) Electron micrograph of the efferent ducts of a normal adult animal immunolabeled with anti—aquaporin-9 (anti—AQP-9) antibody. Numerous gold particles (15 nm, arrowheads) are distributed over the microvilli (Mv) of a nonciliated cell, while few are present in association with small apical endocytic vesicles. 38 000x. (b) Electron micrograph of the apical region of a nonciliated cell immunolabeled with anti—AQP-1 antibody reveals numerous gold particles (10 nm, arrowheads) over the Mv and apical endocytic vesicles (arrows). 52 200x.