Table 1.

Secretion of PDGF-A and PDGF-B into culture medium

Conditioned medium	PDGF-A concentration	PDGF-B concentration
PDGF-IRES-GFP tumor cells	1.46 ± 0.12 ng/ml	29.2 ± 7.4 ng/ml
U87	31.6 ± 16.2 pg/ml	ND
U251	1.41 ± 0.38 ng/ml	ND
U343	52.1 ± 1.64 ng/ml	ND
U373	1.40 ± 0.38 ng/ml	ND

Confluent cultures of human glioma cell lines (U87, U251, U343, and U373) or PDGF-induced tumor cells were grown in basal medium for 24 h. The level of PDGF-A and PDGF-B in each conditioned medium was measured by ELISA. The values represent the mean ± SEM from three separate experiments. ND, Not detected.