Effect of pentobarbital or urethane on bile secretion and chemical composition of blood in the rabbit.

A study was made of the effects of anaesthesia with pentobarbital and urethane on the bile secretion and the chemical composition of the blood of New Zealand rabbits. Neither of the agents was observed to affect arterial pH or pO2, but with urethane pCO2 values decreased significantly. This was associated with a pronounced hyperglycaemia. Bile flow was significantly higher in pentobarbital-anaesthetized animals than in urethane-anaesthetized animals, a phenomenon that can be attributed to a different canalicular flow and that will not be related to differences in the bile-acid-dependent fraction of secretion. Under both anaesthetics, bile sodium concentrations were greater than those found in plasma, which can be explained by the formation of micelles with low osmotic activity. Bile bicarbonate concentrations proved to be greater than those observed in plasma. Plasma calcium concentrations were significantly lower with urethane than with pentobarbital, whereas in bile the situation was reversed; both these aspects are discussed.