Evidence for the absorption of bile acids in the proximal small intestine of normo- and hyperlipidaemic subjects.

Bile acid composition was determined in duodenal and jejunal aspirates obtained under fasting conditions in normolipidaemic controls and in patients with the type IIa and type IV lipoprotein patterns. In 17 out of the 22 subjects studied, the duodenal as compared with the jejunal aspirates contained proportionally more CD (chenodeoxycholic acid) than C (cholic acid). The two types of aspirates also differed slightly with regard to the D (deoxycholic acid): CD ratio, which was higher in samples drawn from the jejunum. These findings, compatible with an absorpiton of about 30% of CD in the upper small intestine, were approximately the same in all groups of patients. As evidenced by additional experiments in two subjects, an oral intake of cream does not significantly influence the absorption of CD in the upper small intestine.