Ovarian expression profiles of PGMRC1 and mPRβ mRNAs during rainbow trout oogenesis (mean ± SEM). Ovaries were sampled from separate females during immature stage (Imm, N = 5 fish, 1000°C. days post-fertilization), pre-vitellogenesis (Pre-vit, N = 6 fish), early vitellogenesis (early vit, N = 6 fish), mid-vitellogenesis (Mid-vit, N = 6 fish), late vitellogenesis (late vit, N = 6 fish), post-vitellogenesis (post-vit, N = 6 fish) and oocyte maturation (Mat, N = 4 fish). The mRNA abundance (mean ± SEM) of each gene was determined by real-time PCR and normalized to the abundance of 18S. For each gene, mRNA abundance was arbitrarily set to 1 for oocyte maturation group. Different letters indicate significant differences between groups (p < 0.05).