Ovine endometrial estrogen receptor expression is altered following PG-600 administration.

Background: Dysregulation of the estrogen receptor 1 (ESR1) expression during the establishment of pregnancy could contribute to reduce fertility reported in ewes treated with PG-600.

Objectives: The objective of this study was to evaluate the effect of treatment with PG-600 on ESR1 expression in the ovine endometrium during early diestrus.

Methods: Polypay ewes (n = 24) that had exhibited an oestrous cycle of normal duration (16-18 days) were treated with intravaginal progesterone-releasing device (CIDR) for 9 days.