EFFECT OF 26,26,26,27,27,27-HEXAFLUORO-1,25-DIHYDROXYVITAMIN D-3 ON THE EXPRESSION OF VITAMIN-D-RESPONSIVE GENES IN VITAMIN-D-DEFICIENT MICE

26,26,26,27,27,27-Hexafluoro-1,25-dihydroxyvitamin D-3 (ST-630) is a n ewly developed agent to maintain the levels of calcium and phosphorus in blood. Herein, we investigated the effect of this compound on the e xpression of vitamin-D-responsive genes in vitamin-D-deficient mice. S T-630 was more effective than 1,25-dihydroxyvitamin D-3 [1,25(OH)(2)D- 3] with respect to the induction of Cyp24 and calbindin-D-9k mRNAs in the kidney and in the small intestine. Moreover, the increase in mRNA levels of vitamin-D-responsive genes induced by ST-630 lasted longer t han that induced by 1,25(OH)(2)D-3. These results indicate that ST-630 was more effective in inducing Cyp24 and calbindin-D-9k gene expressi on than 1,25(OH)(2)D-3 when both compounds were injected into vitamin- D-deficient mice.