C肽灌注对Wistar大鼠胰岛微循环的影响

目的 测定生理剂量重组人C肽静脉注射对雄性Wistar大鼠胰岛微循环、血糖和胰岛素分泌的影响.方法 成年雄性Wistar大鼠分为C肽组和对照组,分别给予C肽(75 nmol/kg体重)和相同容积生理盐水静脉注射;每组再分为葡萄糖组和生理盐水组两个亚组.血流测定采用微球技术.结果 C肽显著增高Wistar大鼠基础胰岛血流[C肽组vs对照组:(0.156±0.018 vs 0.050±0.003)ml·min-1·g-1胰腺,P＜0.01]和胰岛/胰腺血流比值[C肽组vs对照组:(14.33±0.53vs9.16±0.64)%,P＜0.01],胰腺血流向胰岛内重分布.C肽对糖负荷后胰岛微循环无显著影响.C肽降低大鼠腹腔糖耐量试验30 min血糖[C肽组vs对照组:(7.9±0.7 vs 11.5±0.6)mmol/L,P＜0.01];增加胰岛素分泌(AUC胰岛素(0-120),C肽组vs对照组:141.36±15.00 vs 49.78±5.60,P＜0.01).结论 C肽静脉注射改善Wistar大鼠基础胰岛微循环,调节糖负荷后胰岛素分泌.

Effect of C peptide on pancreatic islet microcirculation in Wistar rats

Objective To evaluate the effects of physiological doses of C-peptide on islet microcirculation,blood glucose,and insulin concentrations.Methods Adult male Wistar rats were divided into two groups i.v either with C-peptide (75nmoL/kg body wt)or saline (control).Each group was further divided into 2 subgroups using 1 ml saline or 30% glucose.A microsphere technique was adopted to measure the pancreatic islet microcirculation.Results Intravenous injection of C-peptide markedly increased basal islet blood flow[(0.156±flow[(14.33±0.53 vs 9.16±0.64) %,P＜0.01],but did not affect islet microcircuJation after intravenous glucose administration.In IPGT,C-peptide decreased blood glucose at 30 min[(7.9±0.7 vs 11.5±0.6) mmol/L,P＜0.01]after glucose challenge and stimulated insulin secretion(for AUCins(0.120),141.36±15.00 vs 49.78±5.60,P ＜ 0.01).Conclusion C-peptide induces redistribution of pancreatic blood flow in favour of islet in normoglycemic rats,and modulates insulin release in hyperglycaemic rats.