Fig. 5. Expression of the VDR in mammary gland terminal end bud of wild-type mice. Formalin fixed sections of mammary gland from a 6-week-old virgin wild-type mouse were subjected to immunohistochemistry with a monoclonal antibody directed against VDR. VDR positive cells appear brown against the blue Hematoxylin counterstain. (A) VDR was localized to the nuclei of both stromal and epithelial cells in the terminal end bud. VDR expression was low in the leading edge (box B) compared to the trailing edge (box C). (B) Higher magnification of boxed area B (leading edge of terminal end bud) from A, showing weak VDR staining in highly proliferative cap cells (arrowheads) and epithelial body cells (arrows). (C) Higher magnification of boxed area C (trailing edge of terminal end bud) from A, showing strong nuclear VDR positivity in the luminal and myo-epithelial cells (arrows) and weaker but detectable staining in stromal cells (arrowheads). Scale bar, 50 µm.
