Effect of ursodeoxycholic acid treatment on ileal absorption of bile acids in man as determined by the SeHCAT test

Abstract

The effects of ursodeoxycholic acid on ileal absorption of bile acids and on serum bile acid and lipoprotein concentrations were studied. Eight healthy subjects were investigated. The γ emitting bile acid analogue, SeHCAT, was given orally and its fractional catabolic rate and seven day retention were assessed by repeated external counting over the upper abdomen during the next seven days. Ursodeoxycholic acid was then given oraily at a dose of 15 mg/kg/ day for three weeks and the study was repeated during treatment. The fractional catabolic rate increased by 64% (mean (SD), 0 333 (0.159) v 0.203 (0.061)/day; p<0.05) and seven day retention decreased by 44% (15 (10) v 27 (10)%, p<0.00l), indicating bile acid malabsorption. Total serum cholesterol fell from 5.79 (1.22) to 5 50 (1.18) mmol/l (p=005), while serum ursodeoxycholic acid increased 22 fold (7-87 (2.67) v 0-34 (0.24) iμmol/l, p<0.001). Five of the subjects continued taking 30 mg/kg/day of ursodeoxycholic acid for one week and showed an increase in fractional catabolic rate of 81% (0.300 (0.091) v 0.166 (0.037)/day; p<0.05) and a fall in seven day retention of 50% (16 (12) v 32 (8)%, p<0.01). There were significant reductions in total cholesterol (5.36 (1.71) v 6.08 (1.47) mmol/l; p<0.05) and low density lipoprotein cholesterol (3.70 (1.33) v 4.58 (1.16) mmol/l; p<005). The results support the concept that ursodeoxycholic acid treatment interferes with the absorption of endogenous bile acids, and emphasise the beneficial effects of this treatment on lipoprotein concentrations in man.