Evaluation and diagnostic potential of serum ghrelin in feline hypersomatotropism and diabetes mellitus

J Vet Intern Med. 2015 Jan;29(1):14-20. doi: 10.1111/jvim.12536.

Abstract

Background: Ghrelin is a growth hormone secretagogue. It is a potent regulator of energy homeostasis. Ghrelin concentration is down-regulated in humans with hypersomatotropism (HS) and increases after successful treatment. Additionally, ghrelin secretion seems impaired in human diabetes mellitus (DM).

Hypothesis: Serum ghrelin concentration is down-regulated in cats with HS-induced DM (HSDM) compared to healthy control cats or cats with DM unrelated to HS and increases after radiotherapy.

Animals: Cats with DM (n = 20) and with HSDM (n = 32), 13 of which underwent radiotherapy (RT-group); age-matched controls (n = 20).

Methods: Retrospective cross-sectional study. Analytical performance of a serum total ghrelin ELISA was assessed and validated for use in cats. Differences in serum ghrelin, fructosamine, IGF-1 and insulin were evaluated.

Results: Ghrelin was significantly higher (P < .001) in control cats (mean ± SD: 12.9 ± 6.8 ng/mL) compared to HSDM- (7.9 ± 3.3 ng/mL) and DM-cats (6.7 ± 2.3 ng/mL), although not different between the HSDM- and DM-cats. After RT ghrelin increased significantly (P = .003) in HSDM-cats undergoing RT (from 6.6 ± 1.9 ng/mL to 9.0 ± 2.2 ng/mL) and the after RT ghrelin concentrations of HSDM cats were no longer significantly different from the serum ghrelin concentration of control cats. Serum IGF-1 did not significantly change in HSDM-cats after RT, despite significant decreases in fructosamine and insulin dose.

Conclusion and clinical importance: Ghrelin appears suppressed in cats with DM and HSDM, although increases after RT in HSDM, suggesting possible presence of a direct or indirect negative feedback system between growth hormone and ghrelin. Serum ghrelin might therefore represent a marker of treatment effect.

Keywords: Acromegaly; Cat; Insulin growth factor 1; Pituitary adenomas; Secondary diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cat Diseases / blood*
  • Cat Diseases / diagnosis
  • Cats
  • Cross-Sectional Studies
  • Diabetes Mellitus / blood
  • Diabetes Mellitus / diagnosis
  • Diabetes Mellitus / veterinary*
  • Female
  • Ghrelin / blood*
  • Male
  • Obesity / blood
  • Obesity / veterinary*
  • Retrospective Studies

Substances

  • Ghrelin