Fig. 7.

Cell density modulates the regulation of PKGIβ mRNA levels by TGF-β. Early passage rat AoSMC were seeded on cell culture plates at indicated densities. After 48 h of culture, cells were treated without or with 10 ng/ml TGF-β₁ (open and closed boxes, respectively) for 6 h. PKGIβ and sGCα₁ mRNA levels, relative to 18S RNA levels, were determined using end-point RT-PCR. Although the decrease in sGCα₁ mRNA levels caused by TGF-β₁ treatment was not affected by cell density, the effect of TGF-β₁ on PKGIβ mRNA levels was seen only at higher SMC densities. Data are means ± SD, indexed to the relative mRNA levels obtained in the high-density cells without TGF-β treatment, and typical of 3 independent experiments; n = 6 per group; *P < 0.05.