Effects of PR antagonist on the P-mediated decrease and MPA-mediated increase in TP receptor expression in female rhesus coronary VMC. A, TP receptors in primary coronary VMC from ovx RM treated for 72 h as follows: C, untreated control (lane 1); RU+P, RU486 (1 μm) plus P (1 nm) treatment (lane 2); P, P (1 nm) treatment (lane 3); RU+MPA, RU486 (1 μm) and MPA (10 nm) treatment (lane 4); and MPA, MPA (10 nm) treatment (lane 5). ERK1 detection was used as an internal loading control. B, Quantitation of TP receptor expression. Data are expressed as the mean ± sem and represent results from three independent experiments. *, Significant increase compared with control (P < 0.05); **, significant decrease vs. control VMC (P < 0.05).