Bassett J M
Ann Rech Vet. 1977;8(4):362-73.
The actions of insulin and glucagon in the fetal lamb and regulation of their secretion from the fetal pancreas have been examined to assess the possible roles of these hormones in regulating glucose homeostasis in the lamb during fetal life. Much evidence indicates that insulin stimulated glucose utilization in the fetal lamb and that glucagon can promote mobilization of fetal liver glycogen. Glucose stimulates and adrenaline inhibits insulin secretion by fetal pancrease pieces in vitro from 50 days gestation onwards, but alanine and glycine have little effect on insulin release. Alanine and glycine stimulate glucagon secretion by fetal pancreas pieces in vitro from 50 days gestation. The effects are potentiated by caffeine. Adrenaline has a small stimulatory effect but glucagon release is not altered by glucose. In vivo adrenaline infusion increases fetal plasma glucagon concentrations but glycine infusion does not. Glycine infusion into post-natal lambs increases plasma glucagon. Fasting pregnant ewes for two days decreases plasma insulin but does not alter plasma glucagon in either ewe or fetus. The observations suggest insulin secretion in the fetal lamb is an important determinant of glucose uptake and utilization by the fetus during at least the last third of pregnancy. The quantitative importance of glucagon in regulating fetal hepatic glucose metabolism remains uncertain.
已对胰岛素和胰高血糖素在胎羊体内的作用及其从胎胰分泌的调节进行了研究，以评估这些激素在调节胎羊胎儿期葡萄糖稳态中可能发挥的作用。大量证据表明，胰岛素可刺激胎羊的葡萄糖利用，而胰高血糖素可促进胎肝糖原的动员。从妊娠50天起，葡萄糖可刺激胎胰体外组织块分泌胰岛素，而肾上腺素则抑制其分泌，但丙氨酸和甘氨酸对胰岛素释放几乎没有影响。从妊娠50天起，丙氨酸和甘氨酸可刺激胎胰体外组织块分泌胰高血糖素。咖啡因可增强这些作用。肾上腺素具有轻微的刺激作用，但葡萄糖不会改变胰高血糖素的释放。在体内，输注肾上腺素会增加胎羊血浆胰高血糖素浓度，但输注甘氨酸则不会。向出生后的羔羊输注甘氨酸会增加血浆胰高血糖素。禁食怀孕母羊两天会降低血浆胰岛素，但不会改变母羊或胎儿的血浆胰高血糖素。这些观察结果表明，至少在妊娠最后三分之一期间，胎羊胰岛素分泌是胎儿葡萄糖摄取和利用的重要决定因素。胰高血糖素在调节胎儿肝脏葡萄糖代谢中的定量重要性仍不确定。
