A 10-year-old intact female Cocker Spaniel weighing 15.3 kg presented with dysbasia. The dog had hyperglycemia and glucosuria at presentation. Neurological examination and magnetic resonance imaging on the following day indicated the onset of cervical disk disease. Four days later, the patient returned due to sudden vomiting and anorexia with severe dehydration. Abnormal laboratory findings included severe hyperglycemia with ketonuria. Plasma progesterone concentration was very high at presentation. She was hospitalized for critical care, and insulin administration with fluid therapy was initiated. Mean blood glucose concentration showed a gradual decline, and hyperglycemia with glucosuria disappeared four days after initiation of insulin therapy. This case demonstrated that high plasma progesterone concentration during diestrus can contribute to development of diabetes mellitus in intact female dogs.

• Ji-Houn Kang(Laboratory of Veterinary Internal Medicine, Department of Veterinary Medicine, College of Veterinary Medicine, Chungbuk National University) Corresponding author
• Ah Young Kim(Laboratory of Veterinary Internal Medicine, Department of Veterinary Medicine, College of Veterinary Medicine, Chungbuk National University)
• Mhan-Pyo Yang(Laboratory of Veterinary Internal Medicine, Department of Veterinary Medicine, College of Veterinary Medicine, Chungbuk National University)