Anovulatory luteal cycles in primates.

Area of Science:

• Reproductive Endocrinology
• Primate Models in Reproductive Research
• Follicular Development and Luteinization

Background:

• Understanding the morphology and function of anovulatory luteinized follicles is crucial for reproductive studies.
• Investigating the effects of hormonal and pharmacological interventions on the primate ovarian cycle provides insights into ovulation regulation.

Purpose of the Study:

• To investigate the effects of short-term gonadotropin and prostaglandin synthesis inhibitor therapy on anovulatory luteinized follicles in cynomolgus monkeys.
• To assess the impact of these treatments on ovulation, luteal phase dynamics, and serum progesterone levels.

Main Methods:

• Adult cycling cynomolgus monkeys received human menopausal gonadotropin (hMG), human chorionic gonadotropin (hCG), and prostaglandin synthesis inhibitors (Indomethacin or Naproxen-sodium).
• Treatments were administered during the mid-follicular or late follicular phases of the menstrual cycle.
• Ovarian biopsies, laparotomy, and serum progesterone measurements were used to evaluate follicular morphology, ovulation status, and luteal function.

Main Results:

• Mid-follicular phase treatment led to premature luteinization of follicles and suppressed ovulation in all cycles, with elevated serum progesterone.
• Late follicular phase treatment resulted in luteinization of the dominant follicle and ovulation inhibition in 61% of cycles, with prolonged luteal phases.
• Histological studies confirmed the presence of luteinized follicles, and some cycles showed gross evidence of ovulation.

Conclusions:

• Short-term gonadotropin and prostaglandin synthesis inhibitor therapy can induce anovulatory luteinized follicles and disrupt normal ovulation in non-human primates.
• The timing of treatment influences the degree of follicular luteinization and ovulation suppression, affecting luteal phase characteristics.
• These findings contribute to understanding the mechanisms regulating ovulation and luteinization in the primate reproductive cycle.