CARBOXYLATION OF OSTEOCALCIN IN POSTMENOPAUSAL OSTEOPOROTIC WOMEN FOLLOWING VITAMIN-K AND VITAMIN-D SUPPLEMENTATION

The effect of vitamin supplements on bone metabolism indices in patien ts with osteoporosis has received scant attention in the literature. O ver a 2-week period, vitamin supplements of K and K + D were given to 20 post-menopausal osteoporotic women with previous Colles fractures. Osteoporosis was confirmed by bone mass measurements that demonstrated that broadband ultrasound attenuation (os calcis) was almost as discr iminatory as dual energy X-ray absorptiometry (spine and hip) in Colle s fracture patients compared with matched controls. Vitamin K correcte d the carboxylation defect in osteocalcin and while less marked 4 week s later, the improvement was still detectable. The result after K + D was similar. The level of carboxylation became the same as in premenop ausal women. Total osteocalcin level rose after vitamin K, this rise b eing due to carboxylated (bound) osteocalcin. While there was vitamin K correctable undercarboxylation of osteocalcin, simultaneously there was no evidence of undercarboxylation of prothrombin.