Figure 2.

Stimulation of AA release by growth factors lens epithelial cells. A: Stimulation of AA release from rabbit lens epithelial layer. Two pooled epithelial layers of rabbit lenses were incubated in 6 well culture plate in [¹⁴C]-AA containing 1 ml TC199 medium overnight, washed thoroughly with PBS solution, and then incubated for 60 min in fresh medium in the absence (control) and presence of EGF, IGF or PDGF (5 ng/ml). An aliquot of medium (50 μl) from each well was collected at 2, 5, 10, 20, 30, and 60 min after incubation and counted for radioactivity. Two separate experiments were conducted. The data is expressed as mean±SD. Open diamond: EGF; open circle: IGF; solid triangle: PDGF; solid square: Control (no stimulation). B: Stimulation of AA release by PDGF in HLE B3 cells. Cells (1.3 million) were weaned from serum by incubating at 2% FBS 24 h in the presence of 0.5 μCi/ml [³H]-AA. The cells were washed thoroughly with MEM and pre-incubated 30 min with 10 μM AACOCF₃ (a specific inhibitor for cytosolic PLA₂), or 5 μM U0126 (MEK specific inhibitor) in FBS-free medium before exposed to 50 ng/ml PDGF. The medium (100 μl) was collected at 0, 2.5, 5, 10, and 20 min and counted for labeled AA release. The data shows radioactivity (dpm) from released tritium-AA at different times. The mean±SD are based on four separate experiments. Open circle: control (no PDGF); open square: control + AACOCF₃; open triangle: control + U0126; solid circle: PDGF stimulated cells; solid square: PDGF + AACOCF₃; solid triangle: PDGF + U0126. The single asterisk indicates a p<0.04, the double asterisk indicates a p<0.005, and the triple asterisk indicates a p>0.07.