Fig. 7. Immunofluorescence localisation of cathepsin D in mammary acini of lactating rat. Fragments of the mammary glands of rat were fixed and immunolabelled with anti-cathepsin D (1:100) and FITC-conjugated goat anti-rabbit IgG. (a) Control section treated as described with omission of the primary antibody. (b) DAPI staining of the control section. (c) Cathepsin D is located in cytoplasmic spots (arrow), in the lumen of the acini (L) and strongly accumulated in the basal region of the acini (arrowheads) in close proximity of the basal membrane (BM). Stroma cells are also stained (double arrow). (d) DAPI staining of the section showed in panel c. Bar, 10 µm.