Figure 6.

TRAP⁺ MNC formation in cocultures of spleen cells and primary osteoblasts from PGHS-2^+/+ and PGHS-2^–/– mice. Osteoblasts were pooled from 4 populations from sequentially digested calvariae. Cocultures were treated with 1,25-D (10 nM) or PTH (10 nM), with or without PGE₂ (1 μM) for 7 days and then stained for TRAP. Bars represent mean ± SE of quadruplicate cultures. (a) Cultures were treated with vehicle (open bars), PGE₂ (striped bars), 1,25-D (black bars), or 1,25-D + PGE₂ (gray bars). (b) Cultures were treated with vehicle (open bars), PGE₂ (striped bars), PTH (black bars), or PTH + PGE₂ (gray bars). ^ASignificant difference from vehicle treatment; P < 0.01. ^BSignificant difference from vehicle treatment; P < 0.05. ^CSignificant effect of PGHS-2^–/– osteoblasts; P < 0.01. ^DSignificant difference from treatment with either agent alone; P < 0.01.