Abstract
The effects of vitamin K_2 injection into newborn rats on bone γ-carboxy-glutamic acid-containing protein (BGP) levels in calvaria and serum were ob-served in relation to those on calcium metabolism. Rat BGP was determined by radioimmunoassay using antiserum to purified rat BGP. The injection of vitamin K_2 into the newborn rats at birth and 2 days after birth resulted in the significant decrease of serum BGP levels compared with control rats. However, the non-γ-carboxylated serum BGP levels were decreased by vitamin K_2. On the other hand, bone BGP levels were significantly increased by vitamin K_2. The change of bone BGP levels after vitamin K_2 injection was correlated with the increases of bone calcium, inorganic phosphorus contents and bone alkaline phosphatase activity. These results suggest that vitamin K_2 may directly or indirectly mediate BGP deposition in bone associated with calcium metabolism.
