Cultures were exposed to either vehicle [(-) TGF-β1] or TGF-β1 [(+) TGF-β1; 3ng/ml] followed by the addition of SB431542 (20μM) at the indicated times. At 24 hr (arrow), medium containing LPS plus IFNγ (final = 2μg/ml and 3ng/ml, respectively) was added to cultures. Twenty-four hr later, culture supernatants were collected and NO production (mean μM nitrite accumulation + SEM) was assessed (n = 6 from 3 separate dissections). (*) indicates a significant increase due to TGF-β1, whereas (#) indicates a significant within group SB431542-mediated diminution as compared to CON. Significance, assessed at p<0.05, was determined by two-way ANOVA followed by the Bonferroni's post-hoc test.