Neonatal androgenization in rats affects oocyte maturation.

Area of Science:

• Reproductive Biology
• Endocrinology
• Developmental Biology

Background:

• Androgens play a crucial role in normal ovarian function, follicle, and oocyte maturation.
• Disruptions in androgen levels, either excess or deficiency, can negatively impact ovarian function.

Purpose of the Study:

• To investigate the impact of neonatal androgenization on the first ovulation and oocyte maturation in rats.
• To analyze the effects of early-life androgen exposure on ovarian response to gonadotropin stimulation and subsequent oocyte quality and fertilization.

Main Methods:

• Neonatal rats were administered testosterone, dihydrotestosterone, or vehicle daily during the follicle assembly period.
• Rats were stimulated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) during the juvenile period.
• Analysis included ovulation rates, ovarian histology, hormonal levels, meiotic spindle morphology, and in vitro fertilization (IVF) rates.

Main Results:

• Oocytes from androgenized rats exhibited a higher proportion of aberrant meiotic spindles and altered meiotic progression compared to controls.
• Androgenized rats showed an increased fertilization rate and a higher incidence of aberrant embryos after in vitro fertilization and culture.
• These findings indicate a direct impact of neonatal androgens on oocyte development and quality.

Conclusions:

• Neonatal androgen exposure exerts a programming effect on oocyte development, with consequences observable in adulthood.
• The observed oocyte alterations may contribute to the reduced fertility rates seen in conditions like polycystic ovary syndrome (PCOS) patients undergoing IVF.