Previous studies have shown that the Goto-Kakizaki (GK) rat, a non-obese type 2 diabetes-model, has an increased white adipose tissue (WAT) and islet blood flow when compared to control rats. The aim of the study was to examine if these increased blood flow values in GK rats could be affected by the ₃-adrenoceptor antagonist SR59230A. We measured organ blood flow with a microsphere technique 10 min after administration of SR59230A (1 mg/kg body weight), or the corresponding volume of 0.9% NaCl solution (1 ml/kg body weight) in rats anaesthetized with thiobutabarbital. The GK rat had an increased blood flow in all intra-abdominal adipose tissue depots except for the sternal fat pad when compared to Wistar Furth (WF) rats. However, no differences were seen in the blood perfusion of subcutaneous white or brown adipose tissue. The blood flow was also increased in both the pancreas and in the islets in the GK rat compared to WF rats. SR59230A-treatment affected neither WAT nor pancreatic blood flow in WF rats. In GK rats, on the other hand, SR59230A decreased both WAT and islet blood flow values to values similar to those seen in control WF rats. The whole pancreatic blood flow was not affected by SR59230A-administration in GK rats. Interestingly, the brown adipose tissue blood flow in GK rats increased after SR59230A-administration. These results suggest that ₃-adrenoceptors are involved in regulation of blood flow both in islet and in adipose tissue.