AJP - Gastrointestinal and Liver Physiology, Vol 266, Issue 2 318-G323, Copyright © 1994 by American Physiological Society
Evidence that bile salts are important for iron absorption
A. J. Sanyal, J. I. Hirsch and E. W. Moore
Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
The role of bile salts in intestinal Fe absorption has not previously been
defined. We have recently shown that bile salts having cholanic ring 7
alpha-OH and/or 12 alpha-OH groups bind Fe2+ with high affinity at
premicellar concentrations and also produce a two-to threefold enhancement
in Fe2+ uptake from perfused intestinal segments in vivo. However, the
physiological relevance of these observations for Fe2+ absorption was not
known. To study this, we examined the effects of a single dose of
taurocholate (TC) administered with 59Fe-FeSO4 in reversing iron
malabsorption induced by bile duct ligation. Fe absorption from three
0.5-mg doses of 59Fe-FeSO4 was measured from five groups of six adult
Sprague-Dawley rats each: group 1, before and after bile duct ligation and
subsequent administration of 59Fe-FeSO4 + TC test dose; group 2, before and
after bile duct ligation followed by a third dose of Fe alone; group 3,
before and after bile duct ligation followed by a third dose of
Fe+taurodehydrocholate (TDHC); group 4, sham laparotomy; and group 5,
nonoperated controls where Fe absorption was measured from three doses of
59Fe-FeSO4 at the same time intervals as group 1. Absorption was measured,
using whole body counting, after achievement of steady-state counts after
each Fe dose. Mean percentage absorption from dose 1 (baseline) was 35.33
+/- 4.6% (SE). No significant differences between any groups were noted. In
nonoperated controls (group 4), Fe absorption was virtually identical after
all three doses. Also, hematocrit did not change in any of the 30
animals.(ABSTRACT TRUNCATED AT 250 WORDS)
