Time-dependent stimulation of thrombopoietin (TPO) messenger RNA (mRNA) expression by platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and the phorbol ester 12-myristate 13-acetate (PMA) in human bone marrow (BM) stromal cells.

TPO mRNA expression levels were determined by using a quantitative in situ hybridization (QISH) assay at various time points after the addition of 50 ng/mL PDGF (A), 20 ng/mL FGF (B), or 50 ng/mL PMA (C). The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels in cells exposed to PDGF are also shown (D). The results shown are the mean ± SD values from 5 separate experiments carried out in triplicate. *P < .05 compared with controls (time 0).