Fig. 4.
Cholecystokinin octapeptide (CCK-8, 10−8 M) stimulation of MLC phosphorylation (MLC-p) after muscle cells were treated with 2 doses of P4. A: P4 (10−6 M) inhibited MLC-p induced by CCK-8 in normal cells and muscle cells transfected with plasmid DNA of PGR-B receptor (#,##P < 0.02, determined by ANOVA.). Values are means ± SE; n = 3. P4 (10−7 M) significantly reduced MLC-p induced by CCK-8 (10−8 M) only in cells transfected with PGR-B (*P < 0.03, determined by ANOVA), but this concentration had no effect on normal muscle cells. B: 10−7 M P4 had no effect on MLC-p in response to 10−8 M CCK-8 in controls and muscle cells transfected with PGR-A. There were no significant differences by ANOVA between CCK-8 alone and 10−7 M PG + CCK-8 and PGR-A + 10−7 M P4 + CCK-8. Values are means ± SE; n = 3.