PTH AND 1,25(OH)(2) VITAMIN-D PRIMING TO GROWTH-FACTORS DIFFERENTIALLY REGULATES THE OSTEOBLASTIC MARKERS IN MBA-15 CLONAL SUBPOPULATIONS

The functional modulation of enzymatic activities of alkaline phosphat ase (ALK-P) and neutral endopeptidase (CD10/NEP) in MBA-15.4 and MBA-1 5.6 marrow stromal osteoblastic cells was studied. The hormonal effect s of parathyroid hormone (PTH) and 1,25 (OH)(2)D-3 combined with vario us growth factors (bone morphogenic protein [BMP-2 and BMP-3], TGF bet a and IGF-I) on these cells were monitored. The cell responses of MBA- 15.4, a preosteoblastic cell, and MBA-15.6, a more mature osteoblastic cell, to the growth factors and the hormonal challenge were measured by changes of the enzymatic activities (ALK-P and CD10/NEP). The cellu lar response was not uniform and revealed a differential pattern. (C) 1995 Academic Press, Inc.