Diagnostic Endocrinology: Blood Steroid Concentrations in Neutered Male and Female Rabbits

There is a growing interest in rabbits as pets, and many pet rabbits are neutered to prevent pregnancy and avoid behavioral issues. Behaviors such as mating and aggression in neutered rabbits may suggest incomplete gonadectomy, adrenal disease, or other conditions. Information on adrenal steroid concentrations, including progestins and androgens, in neutered rabbits is not readily available in the literature. In this study, we determined concentrations of the adrenal steroids progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, and cortisol in 29 neutered rabbits. Results revealed no significant differences in hormone concentrations between neutered male and female rabbits. Mean ± standard error and relative percent concentrations of hormones were progesterone 0.25 ± 0.02 ng/mL (1.5%), 17-hydroxyprogesterone 6.40 ± 1.35 ng/mL (39.2%), androstenedione 2.47 ± 0.22 ng/mL (15.0%), testosterone 0.02 ± 0.00 ng/mL (0.12%), and cortisol 7.28 ± 0.40 ng/mL (44.2%). Steroid hormone concentrations determined in this study are an initial step in gaining more information about endocrine function in rabbits and may be useful in diagnostic evaluation of incomplete gonadectomy and adrenal disease in rabbits.