Expression of receptors for ovarian steroids and prostaglandin E2 in the endometrium and myometrium of mares during estrus, diestrus and early pregnancy

The objective of this study was to compare expression of estrogen receptor alpha (ER-α), β (ER-β), progesterone receptor (PR), as well as prostaglandin E2 type 2 (EP2) and 4 (EP4) receptors in the equine myometrium and endometrium during estrus, diestrus and early pregnancy. Tissues were collected during estrus, diestrus, and early pregnancy. Transcripts for ER-α (ESR1), ER-β (ESR2), PR (PGR), EP2 (PTGER2) and EP4 (PTGER4) were quantified by qPCR. Immunohistochemistry was used to localize ER-α, ER-β, PR, EP2 and EP4. Differences in transcript in endometrium and myometrium were compared by the ΔΔCT method. Expression for ESR1 (P