Document Detail

Human prostatic acid phosphatase directly stimulates collagen synthesis and alkaline phosphatase content of isolated bone cells.
MedLine Citation:
PMID:  1653783     Owner:  NLM     Status:  MEDLINE    
Human prostatic acid phosphatase (hPAP) directly enhances the differentiated characteristics of isolated bone cells in vitro. This enzyme, when added to cell cultures for 24 h in vitro stimulates collagen synthesis and the production of alkaline phosphatase. The effects are dose dependent, with statistically significant effects occurring from 0.1-100 nM hPAP. Concentrations higher than 100 nM do not evoke greater effects. The maximal effect of hPAP occurs between 12 and 24 h of exposure. The cells stimulated to the greatest degree are osteoprogenitor cells and osteoblasts. Fibroblasts isolated from the same tissue show a lesser sensitivity to hPAP. hPAP has no detectable effect on cell proliferation, as measured by radiolabeled thymidine incorporation or total DNA synthesis. None of the observations reported in this work can be attributed to contaminating proteins in the hPAP preparation. hPAP was radiolabeled with 125I and was used for affinity binding and cross-linking studies. Scatchard analysis of specific binding indicated the presence of 1.0 X 10(5) high affinity binding sites/cell, with a Kd of 6.5 nM. Cross-linking studies demonstrated the presence of one 320-kDa binding complex. The pH profile and kinetic determinations of Km and maximum velocity for hPAP were similar to those previously reported, except for the finding of positive cooperativity of the substrate with the enzyme under the conditions of our assay. We believe that the direct stimulation of bone-forming cells by hPAP may contribute to the sclerotic nature of skeletal bone around sites of neoplastic prostatic metastases and that the effect of the enzyme is probably mediated by a plasma membrane receptor.
M Ishibe; R N Rosier; J E Puzas
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of clinical endocrinology and metabolism     Volume:  73     ISSN:  0021-972X     ISO Abbreviation:  J. Clin. Endocrinol. Metab.     Publication Date:  1991 Oct 
Date Detail:
Created Date:  1991-10-17     Completed Date:  1991-10-17     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375362     Medline TA:  J Clin Endocrinol Metab     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  785-92     Citation Subset:  AIM; IM    
Department of Orthopaedics, University of Rochester, New York 14642.
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MeSH Terms
Acid Phosphatase / pharmacology*
Alkaline Phosphatase / analysis*,  metabolism
Bone and Bones / cytology*,  enzymology,  metabolism
Cell Separation
Cells, Cultured
Collagen / metabolism*
Dose-Response Relationship, Drug
Fibroblasts / metabolism
Hydrogen-Ion Concentration
Insulin-Like Growth Factor II / metabolism
Iodine Radioisotopes / diagnostic use
Prostate / enzymology*
Receptors, Cell Surface / metabolism,  physiology
Grant Support
Reg. No./Substance:
0/Iodine Radioisotopes; 0/Receptors, Cell Surface; 67763-97-7/Insulin-Like Growth Factor II; 9007-34-5/Collagen; EC Phosphatase; EC Phosphatase

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