A 10-year-old, 8.28 kg, intact female Cocker Spaniel was presented with continuous polyuria and polydipsia. The dog had proestrus bleeding 5 weeks earlier, and hyperglycemia, glucosuria, ketouria, and high level of serum fructosamine in laboratory findings. Based on hyperglycemia, glucosuria, ketouria, and ketosis, the patient was tentatively diagnosed as diabetes mellitus (DM) with ketouria. After diagnosis, 5 to 7 U/body porcine lente insulin was administered during 11 days from initial presentation as the remission of DM for the dog. But, blood glucose was still high level. Because there was no reaction to porcine lente insulin, it was replaced by 4-10 U/body neutral protamine Hagedorn (NPH) during 3 days. But, NPH also did not regulate blood glucose level. Because insulin therapy failed to regulate blood glucose level, the dog was considering insulin-resistant diabetes. The dog was tentatively diagnosed with progesterone-resistant DM on the basis of the history that had revealed proestrus bleeding 5 weeks earlier. Progesterone level was moderate high (43.7 ng/ml; reference range, 15.0-90.0 ng/ml). Ovariohysterectomy (OHE) was performed to remove the cause of the dog's diabetes. After OHE 11 days, blood glucose was gradually declined by insulin treatment. Consequently, blood glucose was well controlled in reference range without insulin treatment after 2 months. This case is a report on progesterone-induced DM treated with OHE and insulin treatment during the diestrus.

Keywords: progesterone, diabetes mellitus, insulin, ovariohysterectomy, dog