EFFECTS OF VITAMIN K ON VITAMIN K DEPENDENT PROTEINS IN NEWBORN INFANTS
Plasma levels of vitamin K (VK) and VK dependent proteins ( factor E, factor VH, factor X, protein C and osteocalcin)were determined before and after VK administration to 22 newborn infants. Vitamin K2 syrup ( 2 mg/kg of body weight ) was orally administered to 9 healthy premature, 11 high risk and 2 VK deficient infants under 3 days of age. VK families extracted from plasma were separated by high performance liquid chromatography using a Cosmosil 5 Ci8 column, and separated VK families were detected by a fluorometry after their reaction with ethanolic sodium borohydride in a reaction coil connected by one-line to a chromatographic column. Total activity of factor E, factor VE and factor X was assayed by a Normotest ( Nyegaard ), and protein C was measured by protac/APTT and protac/chromogenic substrate ( S-2366 ) functional assay system ( American Diagnostica ). Osteocalcin levels were assayed by using of a RIA method before and after the absorption of plasma by hydroxyapatite.After VK administration, plasma VK2 ( menaquinone-4 ) content increased from levels less than 0.012yg/ml to levels between 15.9 and 70.9μg/ml, excluding one case in whom plasma VK was not detected after VK administration. Compared with Normotest values and osteocalcin levels of age-matched healthy newborn infants treated without VK, premature, high risk and VK deficient infant levels significantly increased after 24 hrs and after 7 days of VK administration. No correlation was seen between the increase of plasma VK contents and the increase of Normotest values after VK administration. On the other hand, no significant increase of protein C assayed by both methods was observed in healthy premature and high risk infants after VK administration.These results indicate that the change of protein C after VK treatment is different from that of factor II, VII, X and osteocalcin.