Newly Identified Actions of the Vitamin D Endocrine System*

VITAMIN D is a seco-steroid in which the B-ring of the cyclopentanoperhydrophenanthrene structure is cleaved. The vitamin is either obtained from the diet or is synthesized in the skin from 7-dehydrocholesterol (Fig. 1) and is itself biologically inert (for reviews see Refs. 1–8). Vitamin D and its ... View More