Temporal window in which exposure to estradiol permanently modifies ovarian function causing polycystic ovary morphology in rats

Objective: To investigate the developmental window in which E2 exposure produces irreversible changes in ovarian function resulting in polycystic ovary. Design: Basic experimental study. Setting: University animal laboratory. Animal(s): Thirty Sprague-Dawley rats were administered a single E2 valerate dose (10 mg/kg of weight) at 1, 7, 14, 21, or 30 days of age. Control rats were injected with the vehicle at 1 day of age. All rats were sacrificed at 6 months of age. Intervention(s): Observation of vaginal opening, estrous cyclicity by vaginal smears, and ovarian morphometry in the 6-month-old rat. Main Outcome Measure(s): Measurement of ovarian noradrenaline by high-performance liquid chromatography coupled with electrochemical detection, serum levels of LH by enzyme-linked immunoassay, P, androstenedione, and E 2 by enzyme immunoassay. Result(s): Rats exposed to E2 at 1, 7, or 14 days of life did not show estrual cycling activity and maintained a polycystic ovary (PCO) condition thro