Fig. 5.

Treatment of adipocytes with the PLC inhibitor U73122 (A), the PKC inhibitor RO-31-8425 (B), or the Rho inhibitor Y-27623 (C) blocks the secretion of PAI-I stimulated by incubation with HDL3 or S1P. 3T3 cells were pretreated with 10 μM of U73122 (n = 5), 1 μM RO-31-8425 (n = 4), or 5 μM Y-27623 (n = 7) for 1 h before incubation with HDL2 (800 μg/ml), HDL3 (800 μg/ml), or S1P (0.25 μM) for 24 h. The conditioned medium was removed from each well, and the concentration of PAI-1 was measured using ELISA. Data are presented as mean ± SE. The data were normalized to basal PAI-level obtained from untreated cells (NS). PAI-1 concentration in cultures without any addition averaged 303 ± 51 ng/ml. ^*P < 0.05 and ^**P < 0.01 obtained from ANOVA of PAI-1 level in culture medium from cells incubated with/without the indicated addition in the presence compared with the absence of the chemical inhibitor. Abbreviations: PAI-1, plasminogen activator inhibitor-1; PKC, protein kinase C; PLC, phospholipase C; S1P, sphingosine-1-phosphate.