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

We describe the existence of a specific postnatal window of vulnerability during which estradiol valerate exposure irreversibly programs changes in the follicular development, ovulation, and cyclic estrual activity of rats.

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Authors

Gonzalo Cruz, Ph.D., Rafael Barra, Ph.D., Daniel González, D.V.M., Ramón Sotomayor-Zárate, Ph.D., Hernán E. Lara, Ph.D.

Vol 98, Issue 5, Pages 1283-1290

Abstract

Objective:

To investigate the developmental window in which estradiol exposure produces irreversible changes in ovarian function resulting in polycystic ovary.

Design:

Basic experimental study.

Setting:

University animal laboratory.

Animals:

Thirty Sprague-Dawley rats were administered a single EV dose (10 mg/Kg of weight) at 1, 7, 14, 21 or30 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:

Observation of vaginal opening, estrous cyclicity by vaginal smears, and ovarian morphometry in the 6-month-old rat.

Results:

Rats exposed to estradiol at 1, 7 or 14 days of life did not show estrual cycling activity and maintained a PCO condition throughout the entirety of the study. However, if the exposure to estradiol occurred after postnatal day 21, the PCO-induced condition was reversible. In rats that developed a permanent PCO condition we observed significant effects of estradiol on ovarian morphology if exposure occurred on postnatal day 1 and a presumable effect on the hypothalamus if the exposure occurred between postnatal days 1 and 14.

Conclusion:

Our findings suggest that in rats, the most sensitive period for the promotion of an irreversible PCO morphology by estrogenic compounds is during neonatal early follicular development.

Read the full text at: http://www.fertstert.org/article/S0015-0282(12)01795-5/fulltext


Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. The journal publishes juried original scientific articles in clinical and laboratory research relevant to reproductive endocrinology, urology, andrology, physiology, immunology, genetics, contraception, and menopause. Fertility and Sterility® encourages and supports meaningful basic and clinical research, and facilitates and promotes excellence in professional education, in the field of reproductive medicine.

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