The effect of glucagon, dibutyrylic cyclic AMP and insulin on bile production in the intact rat and the perfused rat liver.

Abstract

The effect of glucagon, dibutyrylic cyclic AMP (DBcAMP) and insulin on bile flow and composition was studied in fasting. Nembutal anesthetized intact rats and perfused rat livers. In intact rats the infusion of glucagon (0.5 microgram x kg b.w.-1 x min-1) resulted in a parallel increase in bile flow and 14C-erythritol clearance of approx. 20%. The biliary excretion rate of electrolytes increased, whereas the net ductular fluid transport and the excretion rate of bile acids remained unchanged. Thus glucagon choleresis in intact rats appears to be due to a stimulation of the bile acid independent fraction of canalicular bile production. A similar effect was seen when DBcAMP (0.5 mumol x kg b.w.-1 x min-1) and insulin (1 U x kg b.w.-1) was given. In the perfused liver glucagon or DBcAMP also increased bile flow. However, bile acid excretion rate also increased and the rise in bile flow was proportional to the rate of taurocholate administration. This effect may be due to uneven distribution of perfusate flow. Insulin was totally without effect on bile production in the perfusion experiments. It is concluded that the choleretic effect of glucagon and insulin is dependent on unknown factors which may be related to extrahepatic actions of the hormones.