Effect of Glucagon on the Metabolism of Lipids and on Urea Formation by the Perfused Rat Liver

Abstract

Livers obtained from fed or fasted rats were perfused with blood from fasted rats with and without the addition of glucagon and/or a hyperlipemic serum (HLS). In addition to its well-known hyperglycemic effect, glucagon increased the blood levels of the ketone bodies and of urea, and decreased the levels of cholesterol, total lipids and NEFA. The magnitude of the effects noted were dependent upon the previous state of the liver and the addition of the hyperlipemic serum. In the fed liver, glucagon produced a greater degree of hyperglycemia than in the fasted liver and this effect was enhanced by the addition of a hyperlipemic serum. In fasted livers the addition of a hyperlipemic serum did not increase the hyperglycemia produced by glucagon alone. Total lipids, cholesterol and NEFA were decreased when glucagon was added to either the fasted or fed liver, in the presence or absence of a hyperlipemic serum. Glucagon caused a greater increase in the level of ketone bodies in the fasted than in the fed liver and this effect was increased by the addition of a serum rich in lipids. The addition of glucagon caused an increase in the levels of urea and this effect was reduced when a hyperlipemic scrum was acMted.