Enterohepatic bile-acid circulation in the pregnant cat

Pregnancy increases the risk of gallstones. The physiological changes responsible for this are not clearly demonstrated. Adjustments in the enterohepatic circulation of bile acids have earlier been studied in pregnancy by methods involving dilution of labelled bile acids. In the present study the bile-acid circulation was measured with direct drainage methods in pregnant animals and controls. It was found that the total bile-acid-pool size was reduced to 65% in the pregnant cat (P less than 0.01) and there was a reduced accumulation of bile acids in the gallbladder after fasting 24 h (P less than 0.01). Bile-acid synthesis by the liver was not reduced and the relation between water and bile-acid secretion by the liver was unchanged. It is concluded that, in the pregnant cat, the bile-acid-pool size is reduced due to a decreased accumulation of bile acids in the gallbladder and an increased interdigestive recycling rate of the bile-acid pool (P less than 0.05). One possible explanation for the reduced accumulation of bile acids in the gallbladder is delayed emptying of the stomach, inducing a late refilling of the gallbladder after a meal.