RETURNYonago Acta medica 1991;34:13-24
Effects of Gastrectomy on the Metabolism of Bile Acids in Rats
Masato Makino, Nobuaki Kaibara, Tetsuo Mura* and Shiro Ikawa*
First Department of Surgery and Division of Chemistry*, Institute of Steroid Research, Faculty of Medicine, Tottori University, Yonago 683, Japan
The effect of gastrectomy on the metabolism of bile acids was examined by analyzing fecal, serum and biliary bile acids in noninbred male Wistar rats. Gastrointestinal continuity was restored by Billroth II anastomosis. Gastrectomy did not change the total fecal excretion of bile acids; however, the proportion of chenodeoxycholic acid and its derivatives (the CDCA group), especially beta-muricholic acid, increased significantly after gastrectomy (P < 0.05). This change in the bile acid profile persisted over the entire 9-month study period. Serum bile acid concentrations and the biliary excretion of bile acids, especially in the unconjugated bile acid fractions, also increased significantly after gastrectomy (P < 0.001). These findings strongly suggest that gastrectomy caused a shortened enterohepatic circulation and a bacterial overgrowth in the upper small intestine. This overgrowth would accelerate the deconjugation of bile salts and the passive absorption of bile acids would increase because of a higher serum concentration of bile acids as well as the biliary excretion of bile acids. The increased proportion of the CDCA group in feces can be explained as a defensive reaction to the increased amount of bile acid absorption.
Key words: bile acids; chenodeoxycholic acid; gastrectomy; shortened enterohepatic circulation