The metabolism of
cholic acid and
chenodeoxycholic acid was studied in seventeen patients with non-operated
Crohn's disease, eleven
ileitis and six
ileocolitis patients. The turnover of
cholic acid was significantly increased in patients with
ileitis (k = 2.01 +/- 1.13 days-1; P less than 0.001) and
ileocolitis (k = 0.91 +/- 0.47 days-1; P less than 0.005) as compared to normals (k = 0.35 +/- 0.19 days-1). Although
chenodeoxycholic acid was better preserved in the enterohepatic circulation than
cholic acid its turnover was also significantly faster in
ileitis (k = 0.81 +/- 0.56 days-1; P less than 0.005) and
ileocolitis patients (k = 0.62 +/- 0.18 days-1; P less than 0.01) than in normals (k = 0.20 +/- 0.09 days-1). The fractional turnover of
cholic acid was related to the length of ileal involvement (r = 0.761; P less than 0.001; n = 17). Patients with Crohn's
ileitis tended to preserve normal fasting total
bile acid pools by increased synthesis of primary
bile acids and efficient absorption of
deoxycholic acid and
ursodeoxycholic acid by the normal colon. Patients with active
ileocolitis had decreased total fasting pool sizes (2.62 +/- 1.83 mmol; P less than 0.001) as compared to normals (7.69 +/- 1.61 mmol). In these patients there was no increase in
bile acid synthesis as compared to normals and secondary
bile acids were absent from bile. It is concluded that the colon has an important role in maintaining the fasting pool size to a normal level in the presence of an interrupted enterohepatic circulation of
bile acids due to
ileal disease.