Osteocalcin bone metabolism marker

The pathogenesis of hepatic osteopathy is primarily characterized by disturbed bone formation due to (7.) reduced osteoblast surface (with the number of osteoblasts being in the normal range) and (2.) reduction in osteocalcin. The latter substance is a bone-matrix protein formed by the osteoblasts. Therefore, the serum value is considered to be a marker of osteogenesis. There is no increase in osteoclasis. The causes and risk factors of disturbed bone metabolism are manifold and not totally understood as yet. (73)... 

Glucocorticoids can even cause osteoporosis when they are used for long-term replacement therapy in the Addison s disease, as has been shown by a study of 91 patients who had taken glucocorticoids for a mean of 10.6 years, in whom bone mineral density was reduced by 32% compared with age-matched controls (SEDA-19, 377 198). However, these results contrasted with the results of a Spanish study in patients with Addison s disease, in which no direct relation was found between replacement therapy and either bone density or biochemical markers of bone turnover of calcium metabolism (alkaline phosphatase, osteocalcin, procollagen I type, parathormone, and 1,25-dihydroxycolecalciferol) (SEDA-19, 377 199). 

It is the most abundant of the noncollagen proteins of bone matrix, accounting for 1% to 2% of total bone protein, or 15% of noncollagen bone protein. Osteocalcin synthesis is induced by physiological concenUations of calcitriol, and the release of osteocalcin into the circulation provides a sensitive marker of vitamin D action and metabolic bone disease (Section 3.5). 

Of current biochemical markers, total ALP or BAP provides the highest clinical sensitivity and specificity in the diagnosis and monitoring of Paget s disease. Although total ALP is most often used, BAP is more sensitive than total ALP in mild Paget s disease. Osteocalcin is relatively insensitive and less useful than BAP in Paget s disease. Total ALP is not useful in metabolic bone diseases with mild elevations of BAP. 

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