Effect of age on androgens pattern in cyclic mares.

Area of Science:

• Veterinary Endocrinology
• Reproductive Physiology in Equines

Background:

• Androgens, produced by adrenal glands and ovaries, are vital for female reproductive functions, including estrogen synthesis and follicular development.
• Aging in mares is associated with reduced androgen concentrations, but the underlying mechanisms remain unclear.

Purpose of the Study:

• To investigate age-related changes in testosterone (T), androstenedione (A4), and dehydroepiandrosterone (DHEA) concentrations in cyclic Spanish Purebred mares.

Main Methods:

• Blood samples were collected from 70 Spanish Purebred mares across five age groups (3-5, 6-9, 10-13, 14-16, and >16 years).
• Hormone concentrations (T, A4, DHEA) were quantified using enzyme immunoassays (EIA) specifically validated for equine use.

Main Results:

• Testosterone concentrations were significantly lower in mares over 16 years compared to younger groups.
• Androstenedione levels were reduced in mares over 16 years compared to all other age groups.
• Dehydroepiandrosterone concentrations were lower in mares aged 14-16 and over 16 years, showing positive correlations with both T and A4.

Conclusions:

• Aging induces a significant reduction in androgen synthesis in physiologically cyclic Spanish Purebred mares.
• These age-related hormonal variations are crucial for accurate interpretation of endocrine data in mares.
• Understanding these changes is essential for equine reproductive health management and research.