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

Abstract

SUMMARYThe effect of glucagon on the rate of glucose production in the presence of alanine, of lactate and of propionate has been studied in isolated perfused livers obtained from foetal, suckling and weaned lambs.Glucose utilization occurred in foetal livers in the absence of glucagon whereas addition of glucagon resulted in a net production of glucose from the three substrates. In livers from suckling and weaned lambs addition of glucagon was not essential for glucose production to occur and the stimulation of gluconeogenesis by added glucagon was less evident in the older lambs. The effect of glucagon was not dependent on changes in the rate of substrate uptake.It is concluded that gluconeogenesis will be induced by glucagon in foetal lambs when their mothers are severely undernourished, and that placentally derived lactate could contribute up to 90% of the glucose synthesized.