FIGURE 1.

ACTH increases FLAG-pro-GX sPLA₂ processing and phospholipase activity secreted by Y1 adrenal cells. Y1 adrenal cells were stably transfected with either a control expression vector (Y1-C) or a vector expressing 3× FLAG-tagged GX sPLA₂ (Y1-GX) and then incubated with 0 or 100 nm ACTH for 20 h. A, phospholipase activity in conditioned media was measured (n = 6). B, conditioned media (20 μl) was immunoblotted using an anti-FLAG antibody (top); results from densitometric analyses are shown below (n = 3). Data are expressed as the ratio of m-GX sPLA₂/total-GX sPLA₂ in the media. C, whole-cell lysates (10 μg of protein) were immunoblotted using anti-FLAG antibody (top) or β-actin (bottom). For comparison, conditioned media from vehicle-treated Y1-GX cells (media) and lysates from Y1-C cells (Y1-C) were also analyzed. Data are means ± S.E. and are representative of three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001.