TITLE:
Pituitary Lesions, Obesity, and Mesenteric Lipomas in Insulin-Resistant Horses
AUTHORS:
Kimberly M. Newkirk, Kelly A. Chameroy, Elizabeth M. Tadros, Barton W. Rohrbach, Nicholas Frank
KEYWORDS:
Body Condition Score, Horse, Insulin Resistance, Mesenteric Lipoma, Pituitary
JOURNAL NAME:
Open Journal of Veterinary Medicine,
Vol.4 No.9,
September
4,
2014
ABSTRACT: The aim of the current study was to identify
associations between pituitary lesions, body condition scores, and mesenteric
lipomas in horses with insulin resistance. Necropsy examinations were performed
following euthanasia in 30 adult horses designated as insulin resistant (n =
11) or insulin sensitive (n = 19). Insulin sensitivity was determined using the
insulin-modified frequently sampled intravenous glucose tolerance test and
resting insulin concentrations. At necropsy, mesenteric lipomas were measured.
The pituitary and adrenal glands, pancreas, and liver were evaluated
histologically; pituitary glands were scored based on published criteria.
Insulin-resistant horses had significantly higher pituitary scores (p = 0.0035)
and body condition scores (p = 0.0001), even when adjusting for age, and a
greater frequency of mesenteric lipomas (p = 0.014) and greater lipoma area (p
= 0.0332) than insulin-sensitive horses. Regardless of insulin status, horses
with pituitary scores ≥3 (diffuse hyperplasia; n = 25) had higher body
condition scores (p = 0.0313) and a greater frequency of mesenteric lipomas (p