Changes in Plasma Testosterone Level and Semen Quality after Frequent Injections of GnRH Analogue in a Beagle Dog with Azoospermia

Abstract

A Beagle with a low plasma testosterone (T) level and azoospermia was given 10 subcutaneous injections of 1 μg gonadotropin-releasing hormone analogue (GnRH-A) per head at intervals of 3 days (Experiment 1), and 6 months after the final injection was given, 15 subcutaneous injections of 2 μg GnRH-A were given at intervals of 2 days (Experiment 2). The plasma T level increased and peaked at 8 weeks after the first injection of GnRH-A in both Experiment 1 and Experiment 2. Motile sperm were detected in the semen collected 8 weeks and 7 weeks after the first injection in Experiment 1 and Experiment 2, respectively. The total number of sperm peaked 9 weeks after the first injection in both Experiment 1 (4.5 × 10⁶) and Experiment 2 (72.8 × 10⁶).