Fibroblast growth factor 23 production in bone is directly regulated by 1{alpha},25-dihydroxyvitamin D, but not PTH. - Saji F; Shigematsu T; Sakaguchi T; Ohya M; Orita H; Maeda Y; Ooura M; Mima T; Negi S (American journal of physiology. Renal physiology, 2010)