Islet blood flow following insulin administration.

Blood flow to the pancreatic islets of the anaesthetised rat was measured using the microsphere method. Basal flow was 29 (+/- 6) microliter/min per pancreas which was equivalent to 2.1 (+/- 0.2)% of the total pancreatic flow. The intravenous administration of 4 IU of soluble insulin, which rendered the animals hypoglycaemic, selectively increased islet flow to 93 (+/- 19) microliter/min per pancreas, equivalent to 5.4 (+/- 0.2)% of total pancreatic flow. It is suggested that this may be related to an enhanced release of glucagon from the islet A cells in response to the hypoglycaemia. Administration of 2.5 ml of a 25% glucose solution intraperitoneally gave rise to hyperglycaemia and produced a similar preferential increase in islet blood flow to 86 (+/- 25) microliter/min per pancreas, 7.4 (+/- 0.2)% of total pancreatic flow.