Microsphere distribution in the pancreas of anesthetized rats
Tóm tắt
Islet blood flow stimulation induced by alloxan leads to an increased blood perfusion in all islets, whereas glucose induces a flow increase only in a subgroup of islets. The aim of the present study was to investigate if an increased islet blood flow was associated with an enhanced total number of perfused islets, or whether only a subgroup of the islets increased their blood flow. For this purpose, the whole pancreatic and islet blood flow was measured with a microsphere technique (4.5×105 microspheres/kg body wt) in anesthetized Sprague-Dawley rats. Blood flow measurements were made 3 min after an iv injection of 1 mL of saline, alloxan (75 mg/kg body wt), ord-glucose (300 mg/mL). Alloxan reduced whole pancreatic blood flow by 50%, but almost doubled islet blood flow. Glucose did not affect whole pancreatic blood flow, but increased islet blood flow 100%. Approximately 10% of the islets in control and glucose-injected rats contained microspheres, compared with about 25% in alloxan-injected rats (P<0.001). When the islets containing a certain number of microspheres were compared, alloxan induced a homogeneous shift of the curve to the right, i.e., increased the number of islets that contained all amounts of microspheres. Glucose preferentially increased only the fraction of islets containing ≥3 microspheres.
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