Abstract

Leuprolide acetate is a long-acting gonadotropin-releasing hormone (GnRH) agonist. Administration initially results in an increase in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) causing transiently elevated testosterone.⁵ In mammals, testosterone suppression usually follows, often approaching zero. Lupron has been used to suppress testosterone and testicular function in Atlantic bottlenose dolphins (Tursiops truncatus),^2,3 to prevent breeding and control aggressive behavior in California sea otters (Enhydra lutris),^1,5-7 to control undesirable male-associated behaviors in California Sea Lions (Zalophus californianus),^3,5 to control mating aggression in pelagic stingrays (Pteroplatytrygon violacea),¹² and for aggression and birth control in lion-tailed macaques (Macaca silenus).¹⁰ It has been shown to lower testosterone levels in black-faced, gray kangaroos (Macropus giganteus), African wild dogs (Lycaon pictus) and spectacled bears (Tremarctos ornatus).⁴ It has also been effective in controlling intermale aggression among gray seals (Halichoerus grypus) and harbor seals (Phoca vitulina) housed together in the same colony (Stremme, unpublished).

Two newly acquired, 2-year-old, unrelated, male African crested porcupines (Hystrix africaeaustralis) began to exhibit aggressive behavior causing wounds requiring veterinary care. Castration was ruled out due to the possibility of future breeding. The monthly form of Lupron was administered intramuscularly to both animals at 0.075 mg/kg every 28 days in an attempt to control the aggression. The animals were anesthetized every 4 weeks with isoflurane, USP to obtain blood to monitor testosterone levels and in some instances to also give the Lupron injections. Serum was sent to the University of Cornell Animal Health Diagnostic Center Endocrinology Laboratory, Ithaca, NY, USA.

Testosterone levels did not drop near zero as expected, and aggressive behavior continued. There was no consistent drop in testosterone levels even when the dose was increased to twice the initial dose (0.150 mg/kg) and three times the initial dose (0.225 mg/kg). In fact, it seemed to rebound and actually increased with the increased dose of Lupron. Leuprolide acetate appears to be ineffective in lowering testosterone levels and in controlling intermale aggressive behavior in African crested porcupines.

Acknowledgments

The authors would like to thank the biologists at the Adventure Aquarium for their professional observations and support in capturing and handling the animals involved in this project.

Literature Cited

1.  Basinger, J.A., H. Walters, P.P. Calle, D.A. Thoney, C. McClave, and M. Hall. Efforts to reduce dominant and aggressive behavior in an all male California sea otter (Enhydra lutris nereis) colony by the use of testosterone suppressing drug therapy. 1997 IMATA Proc.:24.

2.  Briggs, M.B., W. Van Bonn, R.M. Linnehan, D. Messinger, C. Messinger, and S. Ridgway. 1995. Effects of leuprolide acetate in depot suspension on testosterone levels testicular size and semen production in male Atlantic bottlenose dolphins (Tursiops truncatus). IAAAM Proc. on CD-ROM:119–120.

3.  Briggs, M.B., D. Messinger, C. Messinger, R.M. Linnehan, W. Van Bonn, S. Ridgway, and G. Miller. Effects of leuprolide acetate in depot suspension on testosterone levels, testicular size and semen production in male Atlantic bottlenose dolphins (Tursiops truncatus). 1996 AAZV Proc.: 330–332.

4.  Briggs, M.B. Effects of a GNRH agonist on serum sex hormone level of male and female western black-faced, gray kangaroos, male African wild dogs and spectacled bears. 1994 ARAV Proc.:136–139.

5.  Calle, P.P., M.D. Stetter, B.L. Raphael, R.A. Cook, C. McClave, J. Basinger, H. Walters, and K. Walsh. Use of depot leuprolide acetate to control undesirable male associated behaviors in the California sea lion (Zalophus californianus) and California sea otter (Enhydra lutris). IAAAM Proc. on CD-ROM:7–9.

6.  Calle, P.P., B.L. Raphael, R.A. Cook, C. McClave, J. Basinger, and H. Walters. Use of depot leuprolide, cyproterone, and deslorelin to control aggression in an all male California sea otter (Enhydra lutris nereis) colony. IAAAM Proc. on CD-ROM:49–52.

7.  Calle, P.P., C. McClave, J. Basinger, H. Walters, B.L. Raphael, and R.A. Cook. Use of depot leuprolide, cyproterone, and deslorelin to control aggression in an all male California sea otter (Enhydra lutris nereis) colony. 1998 AAZV and AAWV Joint Conference Proc.:375–77

8.  de Oliveira, C.A., G.D. West, R. Houck, and M. Leblanc. Control of musth in an Asian elephant bull (Elephas maximus) using leuprolide acetate. J Zoo Wildl Med. 2004 Mar;35(1):70–6.

9.  Millam, J.R. Reproductive management of captive parrots. Vet Clin North Am Exot Anim Pract. 1999 Jan;2(1):93–110.

10.  Norton, T.M., L.M. Penfold, B. Lessnau, W. Jochle, S.L. Staaden, A. Jolliffe, J.E. Bauman, and J. Spratt. Long-acting deslorelin implants to control aggression in male lion-tailed macaques (Macaca silenus). 2000 AAZV and IAAAM Joint Conference Proc.:201–206 (IAAAM CD-ROM Version) and 174–176 (AAZV CD-ROM Version).

11.  Plosker, G.L., and R.N. Brogden. Leuprorelin. A review of its pharmacology and therapeutic use in prostatic cancer, endometriosis and other sex hormone-related disorders. Drugs. 1994 Dec;48(6):930–967.

12.  Stremme, D.W., N. Grandinetti, and M. Kind. Testosterone levels in a male pelagic stingray (Pteroplatytrygon violacea) after an injection of Lupron (leuprolide acetate) depot given to control aggressive mating behavior. 2007 IAAAM Proc. on CD-ROM: 104–105.