Presence of FPr in porcine corpora lutea (pCLs) at the early-luteal phase (EL-p), the mid-luteal phase (ML-p) and during pregnancy (P-p). A) Relative FPr mRNA expression. The results are presented as Delta Ct (HPRT Ct - FPr Ct). B) FPr protein content. The results are presented as AU (arbitrary units). Data represent mean ± SD. Different letters indicate statistically significant differences (P < 0.05). C) Representative Western blotting of FPr.