In the July 12, 2010, issue of the Archives,1 Grey and Bolland1(p1099) opine “it seems intuitively unlikely that a single hormone could play a substantial role in . . . the diverse range of diseases” linked to vitamin D. Forgetting for a moment the multiform effects of hormones such as cortisol and thyroxine, we note that vitamin D (as calcitriol) is not just a hormone but predominantly an autocrine agent.
Heaney RP, Vieth R, Hollis BW. Vitamin D Efficacy and Safety. Arch Intern Med. 2011;171(3):266. doi:10.1001/archinternmed.2010.528