The effect of insulin and atropine on bile volume and composition

The effects of vagal stimulation by insulin and vagal blockade by atropine, separately and in combination, on bile volume and biliary lipid secretion were studied. Insulin caused a significant increase in acid secretion and bile salt secretion and a brisk choleretic response. Atropine produced a decrease in bile volume and bile salt output. The two together reduced insulin's action on acid secretion and blocked its effect on bile secretion. This suggests that the principal choleretic action of insulin is vagally mediated and the vagus nerve does influence basal bile secretion. The study also shows that bile salt output is increased by vagal stimulation and decreased by vagal blockade.