Fig. 4. Northern blots depicting the effect of 10 µM 15d-PGJ2 on cyclin D1 and GAPDH mRNA levels. A, effect on the quantity of cyclin D1 mRNA in cells treated for 28 h with 15d-PGJ2. B, effect in cells treated for 1 h. The major (4 kb) species of cyclin D1 mRNA is shown. C, vehicle-treated controls; T, treated with 10 µM 15d-PGJ2 for the time periods indicated.