FIGURE 3.

Heparinase reduces HSPG and receptor binding of HB-EGF and FGF-2 but not EGF. SMC were cultured, treated with heparinase (Hep) (0 (□) or (■) 0.1 units/mL), and incubated for 2.5 h with radiolabeled growth factor (0.28 nM ¹²⁵I-FGF-2 (a), 0.42 nM ¹²⁵I-HB-EGF (b), or 0.83 nM ¹²⁵I-EGF (c)—corresponds to 5 ng/mL of each) as described in “Methods” section. Proteoglycan bound (‘salt’) and receptor-bound (‘pH’) growth factor were isolated using sequential washes. Radiolabeled growth factor bound in the presence of excess unlabeled growth factor (5 μg/mL) and released with respective wash is shown in the neighboring gray bar. Measurements (mean ± SE, n = 3) are representative of at least three independent experiments. *Treatment is significantly different than no heparinase (□) treatment within group (salt or pH).^#Treatment is significantly different than heparinase (■) treatment (p < 0.05).