Effects of Exogenous Glucagon on Concentrations of Glucose, Fructose and Insulin in Plasma of Sheep Fetus

Abstract

Exogenous glucagon infused into the fetal sheep resulted in an increase in the concentration of glucose and insulin in fetal arterial plasma without a significant change in the concentration of fructose. Lack of any significant changes in glucagon, insulin, glucose and fructose concentrations in maternal plasma suggests that the alterations in the fetus are secondary to fetal metabolic and hormonal mechanisms rather than reflecting effects of maternal metabolism.

Gluconeogenesis in foetal, suckling and weaned lambs: the effect of glucagon

“…In foetuses of fed ewes the placental supply of glucose closely matches the rate of foetal glucose utilization and hence little or no glucose synthesis by the foetus occurs (Hay et al 1981(Hay et al , 1984. When ewes are fasted there is a gradual increase in the concentration of glucagon in foetal arterial blood (Schreiner, Lemons & Gresham, 1981) and the administration of glucagon into foetal lambs results in an increase in plasma glucose concentration (Schreiner et al 1982) which has been attributed as being most likely due to glycogenolysis (Philipps et al 1983). Our results suggest that an increase in glucagon concentration could promote gluconeogenesis from placentally derived lactate at a rate which would account for 90% of the glucose synthesized by the livers of foetuses from underfed ewes.…”