Effect of the GnRH stimulation test on Canine Prostatic-Specific Esterase (CPSE)

Area of Science:

• Veterinary Medicine
• Reproductive Endocrinology
• Canine Health

Background:

• The gonadotropin-releasing hormone (GnRH) stimulation test assesses testosterone production in male dogs.
• Canine prostatic-specific esterase (CPSE) is a marker for benign prostatic hyperplasia (BPH).
• GnRH testing is often performed alongside CPSE measurements during breeding soundness exams.

Purpose of the Study:

• To determine if GnRH administration alters CPSE concentrations in healthy male dogs.
• To evaluate the impact of two different GnRH protocols (gonadorelin and buserelin) on CPSE levels.
• To inform best practices for diagnostic testing in intact male dogs.

Main Methods:

• Twenty-eight intact adult male dogs underwent clinical and ultrasonographic examinations.
• Two GnRH stimulation protocols were used: gonadorelin (50μg/dog SC) and buserelin (0.12μg/kg IV).
• Serum testosterone (T) and CPSE concentrations were measured before and 1 hour after GnRH administration.

Main Results:

• Both gonadorelin and buserelin effectively increased serum T concentrations.
• Overall, CPSE concentrations did not change significantly after GnRH stimulation in the studied dogs.
• However, 15% of dogs showed a marked increase in CPSE post-GnRH, mimicking BPH values.

Conclusions:

• GnRH stimulation can falsely elevate CPSE levels in some male dogs.
• CPSE should not be assayed from serum samples collected after GnRH administration.
• This finding impacts the interpretation of breeding soundness examinations and prostatic health assessments in dogs.