Expression of oestrogen receptor α and β mRNA in corpus luteum of human subjects

To investigate the role of oestrogen receptor beta (ER beta) in the function of human ovarian corpus luteum, the levels of luteal ER alpha and ER beta mRNA were determined using competitive reverse transcription-polymerase chain reaction-southern blot analysis. The expression of ER alpha and ER beta mRNA was detected in all luteal samples analysed. Luteal ER alpha and ER beta mRNA levels were significantly lower (P < 0.01 and P < 0.05 respectively) at the late secretory phase than those at the early and mid-secretory phases of the endometrium. The ratio of ER alpha to ER beta mRNA levels showed no change during the secretory phase of the endometrium. This study demonstrates that ER beta is co-expressed with ER alpha in human corpus luteum and is likely to play a biological role in the regulation of steroidal action of the corpus luteum with ER alpha.