Dr. Pike’s laboratory is focused on the molecular mechanisms whereby vitamin D, the sex steroids, and other systemic hormones regulate the production as well as cellular activity of bone-forming osteoblasts and bone-resorbing osteoclasts. A long-term area of interest has been in the actions of vitamin D. His laboratory has shown that these actions are mediated by a specific receptor that is localized to the nucleus of target cells and which functions as a transcription factor following activation by its hormonal vitamin D ligand. This research led to the molecular cloning of this factor and elucidation of its regulation and mechanism of action.