VEGF 165 stimulates stromal Tpo and Flt-3 ligand mRNAs. Confluent MS-5 cells (7.5 × 10⁵) were incubated for 72 hours in the absence (lane VEGF 0) or the the presence of either 50 ng/mL (lane VEGF 50) or 100 ng/mL (lane VEGF100) VEGF 165. RT-PCRs were performed using 1 μg of total RNA. Expected PCR products are 270 bp for Flt3-L and 460 bp for Tpo. Amplification of the HPRT mRNA is shown as a control. The intensity of ethidium bromide–stained bands was quantified with a CCD camera and Image Quant v1.11 software (Amersham, Pharmacia Biotech).