Bone turnover in male puberty: a longitudinal study.

In a longitudinal study of male puberty, 18 boys were examined every 3 months for at least 2 years. Serum bone Gla protein (BGP), a biochemical marker of bone formation, was determined and related to changes in serum testosterone (T), serum alkaline phosphatase (AP), serum calcitonin, and bone mineral content (BMC). The data demonstrate a steep increase in serum T during puberty (P less than 0.001), with an almost concomitant increase in serum BGP (P less than 0.001) and serum AP (P less than 0.001). Ten months after the maximal increase in serum T, the increase in BMC reached its maximum, whereas there was no significant change in the serum calcitonin. The data demonstrate that the steep increase in serum T during puberty, directly or indirectly, produces acute stimulation of bone formation (estimated from BGP and AP) followed by a highly significant increase in the integrated measurement of bone apposition (BMC).