[Effect of various levels of vitamin K intake on bone metabolism of rat].

OBJECTIVE

To explore the effect of various levels of vitamin K intake on bone development.

METHODS

Forty weanling Wistar male rats were divided into four groups. In one group, 1% sulfadiazine was added to regular diet (vitamin K 50 micrograms/kg) to induce vitamin K deficiency. In the other three groups, the vitamin K levels in diets were 50 micrograms/kg, 300 micrograms/kg, 2,550 micrograms/kg respectively. Twelve weeks later, the rats were killed and the effects of the different levels of vitamin K intake on bone development were evaluated by the parameters of calcium metabolism, bone metabolic biochemistry, and bone mineral density (BMD).

RESULTS

Vitamin K did not affect the intestinal absorption of calcium. Vitamin K deficiency led to the high levels of urinary calcium and hydroxyapatite excretion, suggesting an increase of bone absorption. Different levels of dietary vitamin K significantly affect circulating osteocalcin and OCbound content. The level of serum2 osteocalcin, OCbound and BMD elevated with the increase of dietary VK levels, whereas the parameters of PTH (thrombo plastin time) were not different between all groups.

CONCLUSION

Vitamin K can enhance the bone development of rat. The rat vitamin K requirement may be higher than that of the current recommendation (50 micrograms/kg).