Fowden A L, Hay W W
Physiological Laboratory, Cambridge.
Q J Exp Physiol. 1988 Nov;73(6):973-84. doi: 10.1113/expphysiol.1988.sp003231.
The effects of fetal pancreatectomy on the uptake and metabolism of glucose were investigated in chronically catheterized sheep fetuses during late gestation by using tracer methodology. Rates of glucose uptake and metabolism were also measured in pancreatectomized fetuses during the infusion of insulin. Pancreatectomy produced hypoinsulinaemia and significantly reduced the rates of fetal glucose utilization and umbilical glucose uptake in comparison to intact fetuses of a similar gestational age. There was no significant alteration in the glucose oxidation fraction after pancreatectomy but because glucose utilization was low in the pancreatectomized fetuses, the rate of fetal glucose oxidation was significantly less after pancreatectomy than in intact animals. No apparent endogenous production of glucose was observed in the pancreatectomized fetuses. Insulin infusion into the pancreatectomized fetuses raised the rates of umbilical glucose uptake and of fetal glucose utilization and oxidation by 40-50% to values similar to those observed in intact animals. The endogenous production of glucose remained negligible during the infusion of insulin into the pancreatectomized fetuses. There was a net flux of radioactive glucose from the pancreatectomized fetus to the uteroplacental tissues and from the uteroplacental tissues into the uterine circulation. These net fluxes and the rate of placental metabolism of tracer glucose decreased significantly during the infusion of insulin into the pancreatectomized fetus. When all the data were combined, partial correlation analyses of the net uteroplacental uptake of tracer glucose and the fetal concentrations of plasma insulin and blood glucose showed that the fetal arterial glucose concentration was the major influence on the net flux of tracer from the fetus to the uteroplacental tissues. These observations demonstrate that the endogenous concentration of insulin has an important role in regulating glucose metabolism in sheep fetus during late gestation.
采用示踪方法，在妊娠晚期对长期插管的绵羊胎儿进行研究，以探讨胎儿胰腺切除术对葡萄糖摄取和代谢的影响。在向胰腺切除的胎儿输注胰岛素期间，还测量了葡萄糖摄取和代谢率。与相同胎龄的完整胎儿相比，胰腺切除术导致胰岛素血症降低，并显著降低了胎儿葡萄糖利用率和脐部葡萄糖摄取率。胰腺切除术后葡萄糖氧化分数无显著变化，但由于胰腺切除的胎儿葡萄糖利用率较低，胰腺切除术后胎儿葡萄糖氧化率明显低于完整动物。在胰腺切除的胎儿中未观察到明显的内源性葡萄糖生成。向胰腺切除的胎儿输注胰岛素可使脐部葡萄糖摄取率、胎儿葡萄糖利用率和氧化率提高40%-50%，达到与完整动物相似的值。在向胰腺切除的胎儿输注胰岛素期间，内源性葡萄糖生成仍然可以忽略不计。放射性葡萄糖从胰腺切除的胎儿向子宫胎盘组织以及从子宫胎盘组织向子宫循环存在净通量。在向胰腺切除的胎儿输注胰岛素期间，这些净通量和示踪葡萄糖的胎盘代谢率显著降低。当所有数据合并时，对示踪葡萄糖的子宫胎盘净摄取与胎儿血浆胰岛素和血糖浓度进行偏相关分析表明，胎儿动脉葡萄糖浓度是示踪剂从胎儿向子宫胎盘组织净通量的主要影响因素。这些观察结果表明，内源性胰岛素浓度在妊娠晚期绵羊胎儿的葡萄糖代谢调节中起重要作用。
