Alkaline phosphatase and tartrate-resistant acid phosphatase in osteoblasts of normal and pathologic bone.
A review of histochemical and immunohistochemical studies on alkaline phosphatase (AP) and tartrate-resistant acid phosphatase (TRAP) in osteoblasts leads to the following conclusions: 1) AP is a typical (non-specific) marker of osteoblasts, and TRAP is a typical (non-specific) marker of osteoclasts; 2) both enzymes may be used to identify the precursors of these cells and are found in young osteocytes; 3) both are released into the extracellular space; 4) both are expressed by metaphyseal osteoblast-like cells whose ultrastructural characteristics are similar to those of post-osteoclastic cells of the basic multicellular unit (BMU) and are also exhibited by osteoblasts and macrophages; 5) the increased numbers of these cells in hypocalcemic animals suggests that the local calcium ion concentration may trigger the transition of the reversal into the formation phase of the BMU.
Bonucci
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Department of Experimental Medicine and Pathology, University La Sapienza, Rome, Italy. ermanno.bonucci@uniroma1.it
Nanci
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D000135:Acid Phosphatase / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D001842:Bone and Bones / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D002118:Calcium / Q000172:deficiency; D020013:Calcium Signaling / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D010006:Osteoblasts / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D010010:Osteoclasts / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D013234:Stem Cells / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D000071681:Tartrate-Resistant Acid Phosphatase
D007527:Isoenzymes; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002118:Calcium