DIABETES-MELLITUS IN A DOG WITH A GROWTH HORMONE-PRODUCING ACIDOPHILIC ADENOMA OF THE ADENOHYPOPHYSIS

A 9-year-old male Doberman Pinscher was referred to the Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University, for polyuria/polydipsia, anorexia, and vomiting. Laboratory examination of blood. and urine revealed hyperglycemia, gl ucosuria, and acidosis. Diabetes mellitus was diagnosed but was very r esistant to subsequent insulin treatment. At the owners' request, the dog was euthanatized and a postmortem examination was performed. In ad dition to hepatic, pancreatic, and renal changes compatible with diabe tes mellitus, an acidophilic adenoma of the adenohypophysis was found. Immunohistochemical staining for growth hormone, adrenocorticotropic hormone, and prolactin showed a strong immunolabeling for growth hormo ne within the cytoplasm of the tumor cells. Although growth hormone le vel was not measured in the plasma, our findings suggest that the diab etes mellitus in this dog was caused by excess growth hormone secreted by the pituitary neoplasm.