Effects of growth factors (A and B), forskolin,
and PMA (C) on FGF-2 content in human astrocytes: Western analysis.
Subconfluent astrocytic cultures were maintained in serum-free medium
containing 0.25% BSA for 24 h before the incubation with growth
factors, PMA, or forskolin. Total cell lysates were subjected to
Western blot analysis as described in MATERIALS AND METHODS. (A and B)
Growth factor concentrations used (PDGFAB, 1 ×
10−10 M; FGF-2, 5 × 10−10 M; IL-1β,
2.8 × 10−10 M [this Figure]; and EGF, 5.0 ×
10−9 M [Figure 2]) are similar to their respective
Kd values (Binger et al.,
1990; Sorkin et al., 1991; Ban et al.,
1993; Stachowiak et al., 1997a) and maximally or near
maximally increased or FGF-2 immunoreactivity in rat (Araujo
and Cotman, 1992) and human astrocytes and astrocyte proliferation (Joy
et al., 1997) (our unpublished observations). Similar
results were obtained in two or three independent experiments with
different astrocytic cultures. (C) Western analysis of PMA- and
forskolin-induced changes in FGF-2 content in human astrocytes.
Subconfluent astrocytes were maintained in serum-free medium for
24 h, after which the cells were treated with forskolin (10 μM)
or PMA (100 nm) for the indicated times. Control cells were incubated
with 0.007% DMSO used as a vehicle for forskolin and PMA. Similar
results were obtained in three independent experiments.