Evaluation of plasma ACTH, alpha-melanocyte-stimulating hormone, and insulin concentrations during various photoperiods in clinically normal horses and ponies and those with pituitary pars intermedia dysfunction.
Abstract: To measure plasma ACTH, alpha-melanocyte-stimulating hormone (aloha-MSH), and insulin concentrations during various photoperiods between February and October in horses and ponies with and without pituitary pars intermedia dysfunction (PPID). Methods: Cohort study. Methods: 13 clinically normal (control) ponies, 14 clinically normal (control) horses, 7 ponies with PPID, and 8 horses with PPID. Methods: Blood samples were collected from February through October during 8 photoperiods: 1, February 13 through March 2; 2, April 4 through 6; 3, June 19 through 22; 4, August 6 through 7; 5, August 14 through 17; 6, September 4 through 6; 7, September 26 through 28; and 8, October 16 through 18. Plasma ACTH, alpha-MSH, and insulin concentrations at each photoperiod were compared among groups. Results: Log ACTH concentration was increased during photoperiod 4 through 8, compared with photoperiod 1 through 3, in all groups. In photoperiod 3 through 7, log ACTH concentrations were higher in horses and ponies with PPID, compared with values for control horses and ponies. alpha-Melanocyte-stimulating hormone (log and raw value) concentration was higher in photoperiod 2 through 8, compared with photoperiod 1, in control horses and ponies. In horses and ponies with PPID, log alpha-MSH concentration was higher in photoperiod 3 through 8, and alpha-MSH concentration was higher in photoperiod 4 through 8, compared with photoperiod 1. In control horses and ponies, plasma insulin concentration was lower in photoperiod 3 than in photoperiod 1. Conclusions: Plasma alpha-MSH and ACTH concentrations increased as daylight decreased from summer solstice (maximum daylight hours) to 12 hours of daylight.
Publication Date: 2009-09-16 PubMed ID: 19751169DOI: 10.2460/javma.235.6.715Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study investigates the levels of ACTH, alpha-MSH, and insulin in the blood of horses and ponies during different periods of daylight (photoperiods) throughout the year, specifically focusing on animals with a certain pituitary gland disorder (PPID) and comparing these to healthy control groups.
Research Objective
- The main objective of this research was to measure and compare the plasma concentrations of ACTH (adrenocorticotropic hormone), alpha-MSH (alpha melanocyte-stimulating hormone), and insulin in horses and ponies suffering from pituitary pars intermedia dysfunction (PPID) and in healthy ones. These measurements were taken during various photoperiods (periods of daylight) ranging from February to October.
Research Design
- In order to conduct this research, a cohort study was designed involving 13 clinically normal (control) ponies, 14 clinically normal (control) horses, 7 ponies with PPID, and 8 horses with PPID.
- Blood samples were collected from all the subjects during eight different photoperiods from February to October.
Featured Analyses
- The study found that ACTH concentration (logarithmically transformed for statistical analyses) in plasma was increased during photoperiods 4 through 8, compared to photoperiods 1 through 3, in all the groups included in the study.
- Furthermore, horses and ponies with PPID had higher ACTH concentrations during photoperiods 3 through 7, when compared to values for the control horses and ponies.
Significant Findings
- Alpha-melanocyte-stimulating hormone (alpha-MSH), a hormone involved in pigmentation, showed higher concentrations in control horses and ponies during photoperiods 2 through 8, compared to photoperiod 1.
- In the horses and ponies with PPID, higher concentrations of alpha-MSH were observed during photoperiods 3 through 8, compared to photoperiod 1. Plasma insulin levels were found to be lower in photoperiod 3 than in photoperiod 1 in control horses and ponies.
- The research concluded that plasma alpha-MSH and ACTH concentrations increase as daylight decreases from summer solstice (maximum daylight hours) to 12 hours of daylight. This finding reflects a clear interaction between photoperiods and hormone levels in both healthy horses and ponies and those with PPID.
Cite This Article
APA
Beech J, Boston RC, McFarlane D, Lindborg S.
(2009).
Evaluation of plasma ACTH, alpha-melanocyte-stimulating hormone, and insulin concentrations during various photoperiods in clinically normal horses and ponies and those with pituitary pars intermedia dysfunction.
J Am Vet Med Assoc, 235(6), 715-722.
https://doi.org/10.2460/javma.235.6.715 Publication
Researcher Affiliations
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348, USA.
MeSH Terms
- Adrenocorticotropic Hormone / blood
- Animals
- Female
- Horse Diseases / blood
- Horses
- Insulin / blood
- Male
- Photoperiod
- Pituitary Diseases / blood
- Pituitary Diseases / metabolism
- Pituitary Diseases / veterinary
- Pituitary Gland, Intermediate / metabolism
- alpha-MSH / blood
Citations
This article has been cited 17 times.- Knowles EJ, Elliott J, Harris PA, Chang YM, Menzies-Gow NJ. Predictors of laminitis development in a cohort of nonlaminitic ponies. Equine Vet J 2023 Jan;55(1):12-23.
- Thane K, Uricchio C, Frank N. Effect of early or late blood sampling on thyrotropin releasing hormone stimulation test results in horses. J Vet Intern Med 2022 Mar;36(2):770-777.
- Karikoski NP, Box JR, Mykkänen AK, Kotiranta VV, Raekallio MR. Variation in insulin response to oral sugar test in a cohort of horses throughout the year and evaluation of risk factors for insulin dysregulation. Equine Vet J 2022 Sep;54(5):905-913.
- Kam YN, McKenzie K, Coyle M, Bertin FR. Repeatability of a thyrotropin-releasing hormone stimulation test for diagnosis of pituitary pars intermedia dysfunction in mature horses. J Vet Intern Med 2021 Nov;35(6):2885-2890.
- Horn R, Stewart AJ, Jackson KV, Dryburgh EL, Medina-Torres CE, Bertin FR. Clinical implications of using adrenocorticotropic hormone diagnostic cutoffs or reference intervals to diagnose pituitary pars intermedia dysfunction in mature horses. J Vet Intern Med 2021 Jan;35(1):560-570.
- 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).
- Hu K, Stewart AJ, Yuen KY, Hinrichsen S, Dryburgh EL, Bertin FR. The effect of freeze-thaw cycles on determination of immunoreactive plasma adrenocorticotrophic hormone concentrations in horses. J Vet Intern Med 2020 May;34(3):1350-1356.
- Hodge E, Kowalski A, Torcivia C, Lindborg S, Stefanovski D, Hart K, Frank N, van Eps A. Effect of thyrotropin-releasing hormone stimulation testing on the oral sugar test in horses when performed as a combined protocol. J Vet Intern Med 2019 Sep;33(5):2272-2279.
- 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.
- Spelta CW. Equine pituitary pars intermedia dysfunction: current perspectives on diagnosis and management. Vet Med (Auckl) 2015;6:293-300.
- Lewis SL, Holl HM, Long MT, Mallicote MF, Brooks SA. Use of principle component analysis to quantitatively score the equine metabolic syndrome phenotype in an Arabian horse population. PLoS One 2018;13(7):e0200583.
- Secombe CJ, Tan RHH, Perara DI, Byrne DP, Watts SP, Wearn JG. The Effect of Geographic Location on Circannual Adrenocorticotropic Hormone Plasma Concentrations in Horses in Australia. J Vet Intern Med 2017 Sep;31(5):1533-1540.
- Banse HE, Holbrook TC, Frank N, McFarlane D. Relationship of skeletal muscle inflammation with obesity and obesity-associated hyperinsulinemia in horses. Can J Vet Res 2016 Jul;80(3):217-24.
- Hart KA, Wochele DM, Norton NA, McFarlane D, Wooldridge AA, Frank N. Effect of Age, Season, Body Condition, and Endocrine Status on Serum Free Cortisol Fraction and Insulin Concentration in Horses. J Vet Intern Med 2016 Mar-Apr;30(2):653-63.
- Giles SL, Nicol CJ, Rands SA, Harris PA. Assessing the seasonal prevalence and risk factors for nuchal crest adiposity in domestic horses and ponies using the Cresty Neck Score. BMC Vet Res 2015 Jan 31;11:13.
- Goodrich EL, Llanos-Soto SG, Ivanek R, Pinn-Woodcock T, Frye E, Wells A, Purdy SR, Berryhill E, Place NJ. Both Season and Equid Type Affect Endogenous Adrenocorticotropic Hormone Concentrations in Healthy Donkeys, Mules and Hinnies in the United States. Animals (Basel) 2026 Jan 16;16(2).
- Viviani P, Lavado RA, Chavarria NH, Ragno VM, Montgomery JB. Spring and fall blood concentrations of adrenocorticotropic hormone, insulin, and thyroxine in healthy horses in Saskatchewan. Can Vet J 2024 Apr;65(4):335-342.
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