Fig. 1. Developmental profile of β-catenin and canonical Wnt signaling in the embryonic and adult adrenal glands. Immunohistochemical analyses of Sf1 (using antiserum A), β-catenin and tyrosine hydroxylase (Th) were performed as described in the Materials and methods. Colorometric determinations of lacZ activity, as a surrogate for active canonical Wnt signaling, in adrenal glands from Wnt-Gal mice at E12.5, E18.5, P0 and P21 were performed as described in the Materials and methods. The black arrowheads highlight lacZ staining in the E12.5 section. Scale bars: 100 µm. The inset in the E12.5 section shows a 40x magnification of the area stained for lacZ. c, adrenal cortex; x, adrenal fetal/X-zone; m, adrenal medulla.