Ovulation in prenatally androgenized ewes

Area of Science:

• Reproductive Endocrinology
• Developmental Biology
• Animal Science

Background:

• Prenatal androgen exposure is known to affect reproductive development in various species.
• Understanding the critical periods of fetal exposure is crucial for comprehending long-term reproductive consequences.

Purpose of the Study:

• To investigate the impact of prenatal testosterone exposure on ovarian activity and estrous cyclicity in ewes.
• To determine if the timing of prenatal androgen exposure influences the severity of reproductive abnormalities.

Main Methods:

• Ewes were exposed to testosterone implants during specific gestational periods (days 30-80, 50-100, 70-120, 90-140).
• Plasma progesterone concentrations were measured daily to assess ovarian activity.
• Ovarian examinations were conducted via laparotomy.

Main Results:

• Ewes exposed to testosterone earlier in gestation (days 30-120) exhibited disrupted estrous cycles and ovulatory failure.
• The incidence of ovulatory failure increased with advancing treatment age within the earlier exposure groups.
• Ewes exposed later in gestation (days 90-140) displayed normal estrous cycles and ovarian activity.

Conclusions:

• The timing of prenatal androgen exposure is critical in determining the effects on ovarian function and estrous cyclicity in ewes.
• Early-to-mid-gestational exposure can lead to persistent reproductive acyclicity and ovulatory dysfunction.