Whole pancreatic blood flow and islet blood flow in hypovolemic hypotension in rats.

The blood volume of adult, male rats was reduced with 5 ml (approximately 30% of the total blood volume) by bleeding, which reduced the mean arterial blood pressure (MAP) to 50 mm Hg. This hemorrhagic hypotension caused an increase in both serum glucose and serum insulin concentrations when compared with either normotensive control animals or with rats infused with nitroprusside to obtain an MAP similar to that of the bled animals. The blood perfusion of the whole pancreas was reduced in both groups of hypotensive animals but more markedly in those with hemorrhagic hypotension. The islet blood flow was reduced only in the bled animals. The percentage fraction of blood diverted through the islet organ was markedly increased in bled rats compared to the control animals, whilst this increase was less pronounced in the nitroprusside-infused rats. The vascular conductance in the nitroprusside-treated rats was unchanged for the whole gland, but increased for the islets. Both these values in bled animals were decreased. It is concluded that the blood flow regulation differs between the endocrine and exocrine parts of the pancreas in hypovolemic hypotension.