Resolution of diabetes mellitus but not acromegaly in a cat with a pituitary macroadenoma treated with hypofractionated radiation

• Published in: Journal of small animal practice Vol. 47; no. 7; pp. 392 - 395
• Main Authors: Littler, R. M., Polton, G. A., Brearley, M. J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-07-2006
• Subjects: Acromegaly - diagnosis; Acromegaly - etiology; Acromegaly - radiotherapy; Acromegaly - veterinary; Adenoma - diagnosis; Adenoma - radiotherapy; Adenoma - veterinary; Animals; Cat Diseases - diagnosis; Cat Diseases - etiology; Cat Diseases - radiotherapy; Cats; Diabetes Mellitus - etiology; Diabetes Mellitus - radiotherapy; Diabetes Mellitus - veterinary; Growth Hormone - secretion; Insulin-Like Growth Factor Binding Protein 1 - analysis; Magnetic Resonance Imaging; Male; Pituitary Neoplasms - diagnosis; Pituitary Neoplasms - radiotherapy; Pituitary Neoplasms - veterinary; Treatment Outcome
• ISSN: 0022-4510; 1748-5827
• DOI: 10.1111/j.1748-5827.2006.00078.x

The use of insulin‐like growth factor 1 assays in the diagnosis and subsequent monitoring after radiotherapy of an acromegalic cat with a secretory pituitary adenoma and secondary insulin‐resistant diabetes mellitus is described. Diabetes resolved, and exogenous insulin was no longer required for the maintenance of normoglycaemia 10 months after completion of a course of hypofractionated radiotherapy. However, insulin‐like growth factor 1 remained elevated, and the cat’s size and appetite continued to increase. It is suggested that radiotherapy may decrease growth hormone concentration to a level such that diabetogenic effects are no longer evident but not to a level required to decrease insulin‐like growth factor 1 secretion.