Prolactin levels in Western Lowland gorillas

Area of Science:

• Reproductive endocrinology
• Primate reproductive biology
• Comparative endocrinology

Background:

• Hyperprolactinemia (elevated prolactin) causes menstrual irregularity and infertility in humans.
• The role of prolactin in menstruation and fertility in Western Lowland gorillas remains largely unknown.

Purpose of the Study:

• To establish a database of prolactin values in female gorillas.
• To correlate prolactin levels with menstrual timing and other reproductive hormones.
• To investigate the impact of prolactin on the reproductive axis in gorillas.

Main Methods:

• Immunoassays were performed on serum specimens from nine female gorillas (dating back to 1983).
• Samples were matched with behavioral data to determine menstrual cycle phase.
• Luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone were measured to assess reproductive status and prolactin's effects.

Main Results:

• Reproductive hormone profiles (LH, FSH, estradiol, progesterone) in gorillas closely resemble those in humans.
• Prolactin levels in gorillas were consistently higher than in humans across most menstrual cycle phases (49.9-93.7 ng/mL).
• Elevated prolactin in gorillas did not appear to suppress the reproductive axis, unlike in humans.

Conclusions:

• Gorillas exhibit higher prolactin levels throughout their menstrual cycle compared to humans.
• Despite high prolactin, the gorilla reproductive axis functions similarly to humans.
• Prolactin may exert a distinct influence on fertility in gorillas compared to humans.