Serum bone Gla protein and other biochemical estimates of bone turnover in early postmenopausal women during prophylactic treatment for osteoporosis.

Serum bone Gla protein (BGP) and conventional biochemical indices of bone metabolism were determined in 66 early postmenopausal women during a double-blind therapeutic trial performed to investigate the effect of oestrogen, calcium and 1,25 (OH)2D3 on postmenopausal osteoporosis. The biochemical variables were determined before, during and after withdrawal of therapy. We found a very high correlation between serum BGP and serum alkaline phosphatase--a measure of bone formation, less high correlation between serum BGP and the remaining parameters--indices of bone resorption. It is concluded that serum BGP probably reflects bone formation and may prove to be a useful new biochemical marker.