Effect of bioactive TGF-β1 on OPG secretion in vivo.

Immunoreactive TGF-β1 (▪), latent TGF-β1 (■), and OPG (▧) were measured in PPP from WT mice infected with 2 × 10⁸ pfu of an adenovirus encoding a mutated TGF-β1 cDNA (Ad-TGF-β1^s223/s225) or the empty adenovirus vector as a control. Plasma was collected 1 month after infection. Each bar represents the mean ± SD of 6 animals. For TGF-β1 determination, samples were assayed prior to acidification (bioactive transgene-encoded, TGF-β1) and after acidification (active + latent forms). Black bar indicates spontaneously active TGF-β1; open bar, latent + active TGF-β1; hatched bar, OPG. Levels of OPG in mice treated with the empty or Ad-TGF-β1 vector are not statistically different (★P < .15).