Diabetes mellitus in cats is often compared with human type 2 diabetes. Pioglitazone, a thiazolidinedione oral insulin sensitizer used in human type 2 diabetics, up-regulates the nuclear transcription factor PPAR-γ, which increases whole body insulin sensitivity and promotes adipocyte uptake and storage of circulating lipids.
This prospective, placebo-controlled 3-way crossover study investigated the effects of pioglitazone on insulin sensitivity and lipid metabolism in obese cats. Obese cats (n = 12) received 7 weeks of each treatment: oral placebo, 1 mg/kg pioglitazone, and 3 mg/kg pioglitazone. Each treatment was followed by a 7-week washout, and each cat received 3 treatments. IV glucose tolerance testing (IVGTT) was performed and serum insulin, nonesterified fatty acids (NEFAs), adiponectin, and leptin measured. Results showed that pioglitazone at 3 mg/kg, as compared with 1 mg/kg and the placebo, significantly increased insulin sensitivity and adiponectin levels and lowered plasma triglycerides and cholesterol. Both pioglitazone doses enhanced NEFA suppression during IVGTT as compared with controls. No adverse effects were noted on physical, laboratory, or echocardiographic examination of study cats. The authors concluded that pioglitazone at 3 mg/kg q24h improves insulin sensitivity and lipid metabolism in obese cats.