Figure 1. Low-power light micrograph of the efferent ducts of a normal adult animal immunostained with anti—aquaporin-1 (anti—AQP-1) antibody. An intense reaction is present over the microvilli (arrowheads) of the nonciliated cells (NC) and cilia of ciliated cells (small arrows) extending deep into the lumen. Also reactive are apical endocytic vesicles (circles) of the nonciliated cells. Sperm (S) in the lumen are unreactive. A faint reaction is visible over myoid cells enveloping the periphery of the tubules (large arrows). IT indicates intertubular space. 420x.