Pituitary pars intermedia dysfunction (equine Cushing’s disease) in a Thoroughbred stallion: a single report.
Abstract: Equine pituitary pars intermedia dysfunction (PPID) generally occurs in older horses showing hirsutism, delayed molting, weight loss, polydipsia, polyuria, laminitis, and reproductive disorders (in broodmares), but there have been no reports on stallions. This report presents a case of a 21-year-old Thoroughbred stallion that developed hirsutism and experienced delayed molting. There were no abnormal findings for semen quality or the stallion's sexual desire. The horse was diagnosed with PPID based on dexamethasone suppression test and plasma levels of adrenocorticotropic hormone. It was then medicated with pergolide mesylate. Since the horse died due to humerus fracture, an autopsy was conducted, and pituitary adenoma was confirmed. No pathological findings were defined in the testicles; therefore, reproductive activity might not have been impaired.
Publication Date: 2016-02-03 PubMed ID: 26858577PubMed Central: PMC4739142DOI: 10.1294/jes.26.125Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Case Reports
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This study focuses on a rare case of Equine pituitary pars intermedia dysfunction (PPID), also known as Cushing’s disease, in a 21-year-old Thoroughbred stallion. The stallion displayed typical PPID symptoms including excessive hair growth (hirsutism) and late shedding of fur (delayed molting), but its reproductive activities appeared unaffected.
Study Details
- The research describes a single case study of PPID in a Thoroughbred stallion, a subject group that has not been heavily explored in prior studies.
- PPID is a condition that usually manifests in older horses with symptoms such as excessive thirst and urination (polydipsia, polyuria), unregulated body weight (weight loss), inflammations in the feet (laminitis) and reproductive disorders. In the highlighted case, the stallion was affected with hirsutism and delayed molting.
- Despite the diagnosis, the reproductive capacity of the stallion, as judged by semen quality and sexual desire, did not appear to be affected. This is an unusual finding, providing an interesting anomaly in the study of PPID.
Examination and Diagnosis
- The horse’s condition was diagnosed as PPID upon administering a dexamethasone suppression test and through measuring plasma levels of adrenocorticotropic hormone, both of which are standard procedures used in identifying this disease.
- The horse was subsequently treated with pergolide mesylate, a common course of treatment for PPID.
Autopsy Findings
- Unfortunately, the patient died during the course of the study due to a fracture in the humerus bone. An autopsy was performed post-mortem which confirmed the presence of a pituitary adenoma, a benign tumor that is commonly associated with PPID.
- Critical to the findings of this study, the autopsy did not reveal any pathology in the testicles, which further suggests that the stallion’s reproductive activity was not influenced by the disease. This challenges the common understanding of PPID, providing a potential avenue for future research.
Cite This Article
APA
Hatazoe T, Kawaguchi H, Hobo S, Misumi K.
(2016).
Pituitary pars intermedia dysfunction (equine Cushing’s disease) in a Thoroughbred stallion: a single report.
J Equine Sci, 26(4), 125-128.
https://doi.org/10.1294/jes.26.125 Publication
Researcher Affiliations
- Kyushu Stallion Station, The Japan Bloodhorse Breeders' Association, Kagoshima 899-8313, Japan.
- Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan.
- Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan.
- Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan.
References
This article includes 11 references
- Boujon CE, Bestetti GE, Meier HP, Straub R, Junker U, Rossi GL. Equine pituitary adenoma: a functional and morphological study.. J Comp Pathol 1993 Aug;109(2):163-78.
- Couëtil L, Paradis MR, Knoll J. Plasma adrenocorticotropin concentration in healthy horses and in horses with clinical signs of hyperadrenocorticism.. J Vet Intern Med 1996 Jan-Feb;10(1):1-6.
- Donaldson MT, McDonnell SM, Schanbacher BJ, Lamb SV, McFarlane D, Beech J. Variation in plasma adrenocorticotropic hormone concentration and dexamethasone suppression test results with season, age, and sex in healthy ponies and horses.. J Vet Intern Med 2005 Mar-Apr;19(2):217-22.
- Heinrichs M, Baumgärtner W, Capen CC. Immunocytochemical demonstration of proopiomelanocortin-derived peptides in pituitary adenomas of the pars intermedia in horses.. Vet Pathol 1990 Nov;27(6):419-25.
- Love S. Equine Cushing's disease.. Br Vet J 1993 Mar-Apr;149(2):139-53.
- McCue P.M.. Ovarian abnormalities. pp. 87–92. In: Current Therapy in Equine Reproduction. (Samper, J.C., Pycock, J.F., and McKinnon, A.O. eds.), W. B. Saunders, Philadelphia.
- McFarlane D, Dybdal N, Donaldson MT, Miller L, Cribb AE. Nitration and increased alpha-synuclein expression associated with dopaminergic neurodegeneration in equine pituitary pars intermedia dysfunction.. J Neuroendocrinol 2005 Feb;17(2):73-80.
- McFarlane D., Toribio R.E.. Pituitary pars intermedia dysfunction. pp. 1262–1270. In: Equine Internal Medicine, 3rd ed. (Reed, S.M., Bayly, W.M., and Sellon, D.C. eds.), W. B. Saunders, Philadelphia.
- Perkins GA, Lamb S, Erb HN, Schanbacher B, Nydam DV, Divers TJ. Plasma adrenocorticotropin (ACTH) concentrations and clinical response in horses treated for equine Cushing's disease with cyproheptadine or pergolide.. Equine Vet J 2002 Nov;34(7):679-85.
- Schott H.C., Graves E.A., Refsal K.R.. Diagnosis and treatment of pituitary pars intermedia dysfunction (classical Cushing’s disease) and metabolic syndrome (peripheral Cushing’s syndrome) in horses. Adv. Derm. 5: 159–169.
- van der Kolk JH, Heinrichs M, van Amerongen JD, Stooker RC, in de Wal LJ, van den Ingh TS. Evaluation of pituitary gland anatomy and histopathologic findings in clinically normal horses and horses and ponies with pituitary pars intermedia adenoma.. Am J Vet Res 2004 Dec;65(12):1701-7.
Citations
This article has been cited 1 times.- Tsuchiya T, Noda R, Ikeda H, Maeda M, Sato F. Relationship between endogenous plasma adrenocorticotropic hormone concentration and reproductive performance in Thoroughbred broodmares. J Vet Intern Med 2021 Jul;35(4):2002-2008.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
