TANAKA Hiroyuki 岡山大学, 医学部附属病院, 助手 (80231413)
KANZAKI Susumu 岡山大学, 医学部附属病院, 助手 (90224873)
黒瀬 裕史 大阪大学, 医学部, 助手 (60192043)
里村 憲一 大阪大学, 医学部, 助手 (60178796)
山岡 完次 大阪大学, 医学部, 助手 (60144490)
|Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1989: ¥1,100,000 (Direct Cost: ¥1,100,000)
23(S), 25(R)-1, 25-dihydroxyvitamin D_3-26, 23-lactone(1, 25-lactone), a physiological metabolite of 1, 25-dihydroxyvitamin D_3(1, 25-(OH)_2D_3), has been shown to have unique actions different'from those of 1, 25-(OH)_2D_3. In contrast to 1, 25-(OH)_2D_3, 1, 25-lactone causes a significant reduction in serum Ca level, stimulates collagen production in osteoblastic cell lines, and inhibits bone resorption induced by 1, 25-(OH)_2D_3. We examined the effect of 1, 25-lactone on ectopic bone formation using a bone-inducing factor and on osteporosis induced by sciatic neurotomy combined with ovariectomy in adult female rats.
1, 25-lactone increased[ ^3H]proline uptake during chondrogenesis and ^<85>Sr uptake during bone formation. Examination using soft X-ray apparatus showed the size and weight of induced bone increased significantly in 1, 25-lactone group by this compound 3 weeks after implantation. Furthermore, small dosis of 1, 25-lactone significantly increased bone formation rate, and prevented the development of osteoporosis. These results suggest that the 1, 25-lactone stimulates bone formation under in vivo conditions.