Vitamin D and psoriasis

Skin can serve as the source of vitamin D when exposed to sunlight so that cutaneous 7-dehydrocholesterol can be converted to the vitamin. Skin is also a target organ for the hormone form of vitamin D: 1,25-(OH)2D3. Both skin keratinocytes grown in tissue culture and samples of human skin have the nuclear receptor for 1,25(OH)2D3. New results suggest that this hormone or its analogs may be effective in treating some forms of psoriasis.