Effects of nuclear receptor antagonists on R1881-, dexamethasone- and at-RA–modulated tube formation. hMVEC were cultured for 8 to 12 days on three-dimensional fibrin matrices in incubation medium containing 20 ng/mL bFGF and 20 ng/mL TNF-α, and to which was added 1 nmol/L R1881 (R1881) (A), 10 nmol/L dexamethasone (dex) (B), or 10 nmol/L at-RA (RA) (C). Receptor antagonists (hydroxyflutamide, RU486 or Ro41-5253; final concentration 1 μmol/L for hydroxyflutamide and RU486 and 10 μmol/L for RO41-5253) or vehicle (0.1% or 0.01% DMSO) were added 1 hour before the hormones. (A) Effect of solvent (DMSO, 0.01% [vol/vol]) or hydroxyflutamide (OH-flu, 1 μmol/L) on tube formation of hMVEC in incubation medium alone (con) or supplemented with R1881 (R1881, 1 nmol/L). (B) Effect of solvent (DMSO, 0.01% [vol/vol]) or RU486 (RU486, 1 μmol/L) on tube formation of hMVEC in incubation medium alone (con) or supplemented with dexamethasone (dex, 10 nmol/L). (C) Effect of solvent (DMSO; 0.1 % [vol/vol]) or Ro41-5253 (Ro41-5253, 10 μmol/L) on tube formation of hMVEC in incubation medium alone (con) or supplemented with all-trans retinoic aicd (at-RA, 10 nmol/L). The data represent the average ± standard deviation of three experiments performed in duplicate and are expressed as percentages of control values (tube-length/cm² in the presence of bFGF and TNF-α).