Description
Vitamin D aids in the absorption of calcium and has central roles in bone formation and maintenance, hypertension, cancer, and immunity. In addition, the active form of vitamin D, 1,25-
dihydroxy vitamin D
3, decreases the proliferation and increases differentiation of keratinocytes. 1,24-
dihydroxy Vitamin D
3 is an analog of 1,25-
dihydroxy vitamin D
3 which, when used in a 4 μg/g ointment, safely and effectively suppresses psoriasis. It also is effective at increasing the time interval between phototherapy cycles when ultraviolet light is used for psoriasis. 1,24-
dihydroxy Vitamin D
3 inhibits the growth of both normal and psoriatic human keratinocytes (IC
50 ~ 10 nM)
via the vitamin D receptor. It also suppresses the production of RANTES and IL-
8 by human dermal fibroblasts and reduces cutaneous lymphocyte-
associated antigen on CD4
+ T cells, impairing migration and skin infiltration.