AJP - Gastrointestinal and Liver Physiology, Vol 271, Issue 4 681-G691, Copyright © 1996 by American Physiological Society
Ileal transposition into the upper jejunum affects lipid and bile salt absorption in rats
T. Tsuchiya, T. J. Kalogeris and P. Tso
Department of Physiology and Biophysics, Louisiana State University Medical Center, Shreveport 71130, USA.
To determine whether ileal transposition affects absorption and transport
of lipids and bile salts, we studied the absorption and lymphatic transport
of triglyceride, cholesterol, and sodium taurocholate in rats with the
distal quarter of their small bowel transposed to the proximal jejunum and
in control rats whose intestines were transected and reanastomosed without
transposition. Three weeks after transposition or sham surgery, rats were
equipped with duodenal or jejunal and intestinal lymph duct cannulas and
then given continuous duodenal or jejunal infusions of lipid emulsion
containing triolein (40 mumol/h + [3H]triolein) and cholesterol (7.8
mumol/h + [14C]cholesterol) for 8 h. Lymph lipid output was measured; after
8 h of lipid infusion, luminal and mucosal radioactive lipid distribution
was also quantified. Transposition had no effect on triglyceride absorption
and transport, but cholesterol absorption and transport were both
significantly attenuated in the transposed rats. In a separate study we
examined whether ileal transposition would alter the kinetics of bile salt
absorption. Six weeks after either transposition or sham surgery, rats were
given a duodenal bolus injection of 14C-labeled sodium taurocholate mixed
in rat bile, and the output of radiolabeled bile salt through a bile
fistula was measured. Appearance of radiolabeled taurocholate was gradual
in the control rats, peaking at approximately 90 min after administration.
Appearance of labeled bile salt was rapid in the transposed rats, peaking
within 60 min after administration. In conclusion, ileal transposition has
no effect on triglyceride absorption but attenuates cholesterol absorption
and transport, possibly by promoting premature absorption of bile salts.
