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Home / Equine Research Bank / Vet Pathol / Immunocytochemical demonstration of proopiomelanocortin-deri...
Veterinary pathology1990; 27(6); 419-425; doi: 10.1177/030098589902700606

Immunocytochemical demonstration of proopiomelanocortin-derived peptides in pituitary adenomas of the pars intermedia in horses.

Abstract: Adenomas of the pars intermedia from 19 horses and normal pituitary glands from seven horses were evaluated histologically and immunocytochemically for adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin (beta-END), proopiomelanocortin (POMC), prolactin, neuron specific enolase, and glial fibrillary acidic protein (GFAP). The 26 horses ranged in age from 7 to 31 years. Histologically, all adenomas had a uniform pattern characterized by cords of large columnar cells forming palisades and pseudoacini separated by a delicate fibrovascular stroma. Immunostaining of adenomas derived from the pars intermedia was similar to that of non-neoplastic equine pars intermedia. An immunocytochemical evaluation revealed a diffuse, strong cytoplasmic reaction for POMC, a moderate to strong reaction for alpha-MSH and beta-END, a weak reaction for ACTH, and negative immunostaining for prolactin, GFAP, and neuron specific enolase in the adenomas. The unique clinicopathologic syndrome that develops in horses with pituitary adenomas appears to be the result of an over-production of POMC-derived peptides in addition to space-occupying effects resulting in dysfunction of the hypothalamus and neurohypophysis.
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Publication Date: 1990-11-01 PubMed ID: 2177580DOI: 10.1177/030098589902700606Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

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 investigates pituitary adenomas in horses, specifically identifying the presence of various hormones and proteins in these tumours. The researchers found that the tumours resulted in the over-production of certain peptides, which may be the leading factor in the syndromes developed by horses with these adenomas.

Research Context

  • The researchers evaluated adenomas (benign tumors) of the pars intermedia, a part of the pituitary gland in horses. They examined samples from 19 horses with adenomas and compared them to normal pituitary glands from seven horses.
  • The focus of the investigation was on several hormones and proteins, including adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin (beta-END), proopiomelanocortin (POMC), prolactin, neuron specific enolase, and glial fibrillary acidic protein (GFAP).
  • The horses involved in the study ranged in age from 7 to 31 years.

Findings and Interpretations

  • On examination, all adenomas had a similar pattern composed of large columnar cells forming rows and pseudoacini (false glandular structures) separated by delicate fibrovascular stroma (connective tissue).
  • Upon using an immunocytochemical approach, the researchers were able to observe the response of these adenoma cells to different hormones and proteins.
  • A strong cytoplasmic reaction was detected for POMC, suggesting an overproduction of POMC-derived peptides within the tumour cells.
  • Similarly, a moderate to strong reaction was seen for alpha-MSH and beta-END, which are derived from POMC.
  • There was a weak reaction for ACTH, and no reaction for prolactin, GFAP, and neuron specific enolase. This suggests that these substances were not significantly produced or affected by the adenomas.

Conclusion and Implications

  • From these observations, the researchers concluded that the unique syndrome, likely characterized by certain physical and behavior changes, seen in horses with pituitary adenomas could be a consequence of the overproduction of POMC-derived peptides.
  • This overproduction and presence of these adenomas, by occupying space and causing dysfunction of the hypothalamus and neurohypophysis (parts of the pituitary), can lead to the said syndrome.
  • The findings of this study can help in understanding the pathophysiology of equine pituitary adenomas and potentially aid in the development of targeted treatments.

Cite This Article

APA
Heinrichs M, Baumgärtner W, Capen CC. (1990). Immunocytochemical demonstration of proopiomelanocortin-derived peptides in pituitary adenomas of the pars intermedia in horses. Vet Pathol, 27(6), 419-425. https://doi.org/10.1177/030098589902700606

Publication

Veterinary pathology
ISSN: 0300-9858
NlmUniqueID: 0312020
Country: United States
Language: English
Volume: 27
Issue: 6
Pages: 419-425

Researcher Affiliations

Heinrichs, M
  • Institut für Veterinär-Pathologie, Justus-Liebig-Universität, Giessen, Federal Republic of Germany.
Baumgärtner, W
    Capen, C C

      MeSH Terms

      • Adenoma / chemistry
      • Adenoma / pathology
      • Adenoma / veterinary
      • Adrenocorticotropic Hormone / analysis
      • Animals
      • Female
      • Glial Fibrillary Acidic Protein / analysis
      • Horse Diseases / metabolism
      • Horse Diseases / pathology
      • Horses
      • Immunohistochemistry
      • Male
      • Peptides / analysis
      • Phosphopyruvate Hydratase / analysis
      • Pituitary Neoplasms / chemistry
      • Pituitary Neoplasms / pathology
      • Pituitary Neoplasms / veterinary
      • Pro-Opiomelanocortin / analysis
      • Prolactin / analysis
      • alpha-MSH / analysis
      • beta-Endorphin / analysis

      Citations

      This article has been cited 19 times.
      1. Drozdzewska K, Gehlen H. Markers for internal neoplasia in the horse. Vet Med Sci 2023 Jan;9(1):132-143.
        doi: 10.1002/vms3.1042pubmed: 36495211google scholar: lookup
      2. Kirkwood NC, Hughes KJ, Stewart AJ. Prospective Case Series of Clinical Signs and Adrenocorticotrophin (ACTH) Concentrations in Seven Horses Transitioning to Pituitary Pars Intermedia Dysfunction (PPID). Vet Sci 2022 Oct 17;9(10).
        doi: 10.3390/vetsci9100572pubmed: 36288186google scholar: lookup
      3. Kirkwood NC, Hughes KJ, Stewart AJ. Pituitary Pars Intermedia Dysfunction (PPID) in Horses. Vet Sci 2022 Oct 10;9(10).
        doi: 10.3390/vetsci9100556pubmed: 36288169google scholar: lookup
      4. Fortin JS, Hetak AA, Duggan KE, Burglass CM, Penticoff HB, Schott HC 2nd. Equine pituitary pars intermedia dysfunction: a spontaneous model of synucleinopathy. Sci Rep 2021 Aug 6;11(1):16036.
        doi: 10.1038/s41598-021-95396-7pubmed: 34362943google scholar: lookup
      5. Ghatnatti V, Vastrad B, Patil S, Vastrad C, Kotturshetti I. Identification of potential and novel target genes in pituitary prolactinoma by bioinformatics analysis. AIMS Neurosci 2021;8(2):254-283.
        doi: 10.3934/Neuroscience.2021014pubmed: 33709028google scholar: lookup
      6. Tatum RC, McGowan CM, Dean RS, Ireland JL. Equine pituitary pars intermedia dysfunction: Identifying research priorities for diagnosis, treatment and prognosis through a priority setting partnership. PLoS One 2021;16(1):e0244784.
        doi: 10.1371/journal.pone.0244784pubmed: 33395695google scholar: lookup
      7. Gehlen H, Schwarz B, Bartmann C, Gernhardt J, Stöckle SD. Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys. Animals (Basel) 2020 Dec 8;10(12).
        doi: 10.3390/ani10122335pubmed: 33302557google scholar: lookup
      8. Fortin JS, Benskey MJ, Lookingland KJ, Patterson JS, Howey EB, Goudreau JL, Schott HC 2nd. Restoring pars intermedia dopamine concentrations and tyrosine hydroxylase expression levels with pergolide: evidence from horses with pituitary pars intermedia dysfunction. BMC Vet Res 2020 Sep 25;16(1):356.
        doi: 10.1186/s12917-020-02565-3pubmed: 32977825google scholar: lookup
      9. Lloyd RV, D'Amato CJ, Thiny MT, Jin L, Hicks SP, Chandler WF. Corticotroph (Basophil) invasion of the pars nervosa in the human pituitary: Localization of proopiomelanocortin peptides, galanin and peptidylglycine α-amidating monooxygenase-like immunoreactivities. Endocr Pathol 1993 Jun;4(2):86-94.
        doi: 10.1007/BF02914457pubmed: 32138413google scholar: lookup
      10. Morgan RA, Keen JA, Homer N, Nixon M, McKinnon-Garvin AM, Moses-Williams JA, Davis SR, Hadoke PWF, Walker BR. Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction. Endocrinology 2018 Nov 1;159(11):3791-3800.
        doi: 10.1210/en.2018-00726pubmed: 30289445google scholar: lookup
      11. Heinrichs M, Ernst H. Spontaneous malignant craniopharyngioma in an aged Wistar rat. J Toxicol Pathol 2016 Jul;29(3):195-9.
        doi: 10.1293/tox.2016-0004pubmed: 27559246google scholar: lookup
      12. Hatazoe T, Kawaguchi H, Hobo S, Misumi K. Pituitary pars intermedia dysfunction (equine Cushing's disease) in a Thoroughbred stallion: a single report. J Equine Sci 2015;26(4):125-8.
        doi: 10.1294/jes.26.125pubmed: 26858577google scholar: lookup
      13. Kimitsuki K, Boonsriroj H, Kojima D, Park CH. A case report of feline pituitary carcinoma with hypercortisolism. J Vet Med Sci 2014 Jan;76(1):133-8.
        doi: 10.1292/jvms.13-0373pubmed: 24025433google scholar: lookup
      14. Reid SW, Mohammed HO. Longitudinal and cross-sectional studies to evaluate the risk of sarcoid associated with castration. Can J Vet Res 1997 Apr;61(2):89-93.
        pubmed: 9114958
      15. Massardi E, Gaudenzi G, Carra S, Oldani M, Rybinska I, Persani L, Vitale G. Cushing's Disease in the Animal Kingdom: Translational Insights for Human Medicine. Int J Mol Sci 2025 Sep 4;26(17).
        doi: 10.3390/ijms26178626pubmed: 40943544google scholar: lookup
      16. Menzies-Gow NJ. Equine Pituitary Pars Intermedia Dysfunction. Vet Sci 2025 Aug 20;12(8).
        doi: 10.3390/vetsci12080780pubmed: 40872730google scholar: lookup
      17. Fouché N, Doras C, Schüpbach-Regula G, Scherer A, Freudenschuss B, Gerber V. Association Between Adrenocorticotropic Hormone Concentration and Clinical Signs of Pituitary Pars Intermedia Dysfunction in Swiss and Austrian Equids. J Vet Intern Med 2025 Mar-Apr;39(2):e70008.
        doi: 10.1111/jvim.70008pubmed: 40095750google scholar: lookup
      18. de Preux M, Precht C, Guevar J, Graubner C, Thenhaus-Schnabel S, Buser L, Lukes A, Koch C. A transmandibular lateral transsphenoidal navigated surgical approach to access a pituitary macroadenoma in a warmblood mare. Vet Q 2024 Dec;44(1):1-10.
        doi: 10.1080/01652176.2023.2300947pubmed: 38393300google scholar: lookup
      19. Takahashi N, Chambers JK, Ota K, Toda K, Yoshimoto Y, Miyajima U, Uchida K. Pituitary pars intermedia dysfunction with pituitary gland melanotroph adenoma in a Grevy's zebra (Equus grevyi). J Vet Med Sci 2024 Jan 10;86(1):71-76.
        doi: 10.1292/jvms.23-0177pubmed: 37981318google scholar: lookup
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