K. Notoya et al., SIMILARITIES AND DIFFERENCES BETWEEN THE EFFECTS OF IPRIFLAVONE AND VITAMIN-K ON BONE-RESORPTION AND FORMATION IN-VITRO, Bone, 16(4), 1995, pp. 349-353
The effects of ipriflavone and vitamin K on bone metabolism were exami
ned using a culture system, Vitamin K-1 and vitamin K-2 (10(-7)M-10(-5
)M) inhibited both the activation of mature osteoclasts and the format
ion of new osteoclasts without affecting the growth of progenitor cell
s in cultures of mouse unfractionated bone cells, The inhibitory effec
ts of vitamin K on bone resorption were similar to those of ipriflavon
e and were not affected by the vitamin K antagonist warfarin, When ipr
iflavone was added to the culture medium in combination with vitamin K
-2, an additive inhibitory effect on bone resorption was observed. An
additive effect was also observed in organ cultures of mouse calvaria,
On the other hand, ipriflavone, but neither vitamin K-1 nor vitamin K
-2, stimulated cellular alkaline phosphatase (ALP) activity on rat bon
e marrow stromal cells under culture conditions in which cells subsequ
ently form mineralized bone-like tissue, Vitamin K-1 and vitamin K-2 a
lso did not modulate the stimulatory effect of ipriflavone on the ALP
activity of the cells, These results suggest that the inhibitory effec
ts of vitamin K on bone resorption are similar to those of ipriflavone
through mechanisms that may be independent of the gamma-carboxylation
system, while the effects of vitamin K on osteoblast phenotype expres
sion are different from those of ipriflavone.