J Clin Invest. 1986 Jan;77(1):7-12. Oral intake of phosphorus can determine the serum concentration of 1,25-dihydroxyvitamin D by determining its production rate in humans. Portale AA, et al. Changes in the oral intake of phosphorus could induce the reported changes in the serum concentration of 1,25-dihydroxyvitamin D (1,25-(OH)2D) by inducing changes in its production rate [...]