活性型ビタミンD

抄録

Since the discovery of 1, 25-dihydroxyvitamin D₃, our knowledge of the metabolic activation and the mode of action of vitamin D has expanded dramatically during the past 15 years. About 40 kinds of the metabolites were isolated. Many analogs of those metabolites have been synthesized in order to obtain higher activity and to separate various biological activities. Recently, a specific receptor for 1, 25- (OH) ₂D₃ was demonstrated in many tissues and tumor cells, and the induction of cell differentiation of myeloid leukemia cells by 1, 25- (OH) ₂D₃ was reported. Vitamin D analogs have been tested for the activity. Usually parallel activities were observed for the calcium regulation effect and cell differentiation. Synthetic analogs, 24-homo-1, 25- (OH) ₂D₃, 26, 27-diethyl-1, 25- (OH) ₂D₃, and 24, 24-F₂-24-homo-1, 25- (OH) ₂D₃ were found to be 10 fold more potent than 1, 25- (OH) ₂D₃ in inducing differentiation of HL-60 cells, but almost inactive in calcium regulation. Thus, the separation of two major actions of 1, 25- (OH) ₂D₃ could be achieved.