25-hydroxycholecalciferol, the active form of vitamin D--Wisconsin scores again.

Abstract

IT is fitting that the discovery of an essential biotransformation of vitamin D should come from the same laboratory in which Harry Steenbock, almost half a century ago, showed that irradiation increased vitamin D content of foods.* Hector DeLuca and his associates have now identified 25-hydroxycholecalciferol as the active metabolite of vitamin D3.† This finding may explain some perplexing features of the vitamin's action. Prior studies showed that the stimulation of active calcium transport in the intestine by vitamin D requires DNA-dependent RNA synthesis and the formation of new proteins. One of these is a calcium-binding protein isolated . . .