Differences in the vascular response to terbutaline in the native and transplanted rat pancreas

Syngeneic pancreaticoduodenal transplantations were performed in Wistar-Furth rats. Fourteen days after implantation, blood perfusion of the whole native and transplanted pancreas, the pancreatic islets and the native and transplanted duodenum was measured with a microsphere technique 5 min after an intravenous injection of 0.5 ml of either saline (n = 6) or terbutaline (1 mg/kg BW; n = 9). Terbutaline decreased the mean arterial blood pressure by approximately 30% (p < 0.001). The substance also decreased the whole pancreatic blood flow of the native pancreas (p < 0.05), but not of the transplanted gland. However, the vascular conductance of the whole pancreas was unchanged after terbutaline administration in both the native and transplanted gland. Islet blood flow (p < 0.001) and islet vascular conductance (p < 0.01) were markedly decreased in the native pancreas. In the transplanted gland, there was, however, no change in islet vascular conductance and only a slight decrease in islet blood flow (p < 0.05). Both the native and transplanted duodenal blood flows were unaffected by terbutaline. One likely explanation for the different effects of terbutaline on the blood perfusion of the native and transplanted pancreas may be that the latter gland is devoid of any physiologically relevant exogenous innervation.