Carlsson P-O, Jansson L, Palm F
Department of Medical Cell Biology, Biomedical Center, Uppsala University, Uppsala, Sweden.
Acta Physiol Scand. 2002 Dec;176(4):275-81. doi: 10.1046/j.1365-201X.2002.01049.x.
The present study investigated the importance of a tightly regulated islet blood flow for an optimal oxygenation of the islet tissue during different demands for insulin release. Glucose and/or a non-specific nitric oxide synthase inhibitor (L-NNA) were infused intravenously in non-pretreated or vagotomized rats and the animals were subjected to measurements of islet blood flow, oxygen tension and serum insulin concentrations. Islet blood flow was measured using a non-radioactive microsphere technique, tissue oxygen tension was recorded with Clark microelectrodes and insulin concentrations were determined by enzyme-linked immunosorbent assay technique. Administration of L-NNA (0.3 mg kg(-1) min(-1)) for 10 min halved basal islet blood flow, but did not affect serum insulin concentrations. Glucose administration (10 mg kg(-1) min(-1)) induced a marked increase in islet blood flow, which could be prevented by vagotomy or L-NNA. The serum insulin concentrations increased in all glucose-infused animals. The islet tissue oxygen tension remained similar in all animals despite these interventions. Reasons other than oxygenation of the islet tissue must explain the normally existing tight regulation of islet blood flow.
本研究调查了在不同胰岛素释放需求期间，严格调节的胰岛血流对胰岛组织最佳氧合作用的重要性。将葡萄糖和/或非特异性一氧化氮合酶抑制剂（L-NNA）静脉注射到未经预处理或迷走神经切断的大鼠体内，并对动物进行胰岛血流、氧张力和血清胰岛素浓度的测量。使用非放射性微球技术测量胰岛血流，用Clark微电极记录组织氧张力，并用酶联免疫吸附测定技术测定胰岛素浓度。以0.3 mg kg⁻¹ min⁻¹的剂量给予L-NNA 10分钟，使基础胰岛血流减半，但不影响血清胰岛素浓度。给予葡萄糖（10 mg kg⁻¹ min⁻¹）可使胰岛血流显著增加，迷走神经切断或L-NNA可阻止这种增加。所有输注葡萄糖的动物血清胰岛素浓度均升高。尽管进行了这些干预，但所有动物的胰岛组织氧张力仍保持相似。除胰岛组织氧合作用外的其他原因必须解释正常存在的胰岛血流严格调节。
