The effect of glucagon, dibutyrylic cyclic AMP and theophylline on bile production in the cat

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Abstract
The effect of glucagon, dibutyrylic cyclic[c]AMP and theophylline on bile production and liver metabolism was studied in fasting, chloralose anesthetized cats. After 45 min infusion of glucagon (0.1 .mu.g/kg per min) total bile flow started to increase and finally reached a level 32% about control bile flow. The rise in flow was accompanied by a parallel increase in the biliary clearance of erythritol and the rate of biliary excretion of inorganic ions, whereas the bile acid excretion remained constant. Glucagon appears to stimulate selectively the bile acid-independent canalicular production of bile. In contrast to the delayed action on bile production, glucagon caused an immediate change in liver metabolism as judged from the elimination rate of ethanol and the rise in plasma glucose concentration. Dibutyrylic cAMP or theophylline also caused similar immediate changes in liver metabolism, but neither substance influenced bile production or the biliary excretion of electrolytes or bile acids. Glucagon choleresis in the cat is either independent of cAMP release or an increase in intracellular cAMP is not in itself sufficient to influence bile secretion. An increase in insulin production induced by hyperglycemia, or hemodynamic changes in the liver, may not explain glucagon choleresis.