Fluid Secretory Responses
to Enterotoxin STa and 8-bromo-cyclic GMP in Fed and
Nutrionally-Deprived Gerbils: Jejunum, Ileum and Colon in vivo
FAWZIA YAQOUB AL-BALOOL
Department of Biological Sciences, Faculty of Science, Kuwait
University, Safat, State of Kuwait.
Received September 17, 2003
Accepted November 6, 2003
Summary
Fluid transport was measured gravimetrically in vivo in the
jejunum, ileum and colon of fed, fasting (four days) and
undernourished (50 % of control food intake for 21 days) gerbils
(Gerbillus cheesmani). The effects of luminal enterotoxin
Escherichia coli STa (50 ng/ml) and luminal 8-bromo-cyclic GMP
(cGMP 1 mM) on fluid transport across jejunum, ileum and colon
were also assessed. Fasting and undernourishment reversed the
normal basal fluid absorption measured in fed ileum and colon
into secretion. Neither fasting nor undernourishment had any
effect on jejunal basal fluid absorption. In jejuna, ilea and
colons of fed animals as well as in jejuna from fasting and
undernourished gerbils STa (50 ng) reversed the normal
absorptive tone to secretion but it had no significant effects
on fluid secretion in either the ileum or colon from fasted
gerbils. STa increased significantly the fluid secretion in
ileum from undernourished gerbils. Luminal cGMP had no effect on
basal absorptive tone in the jejunum of fed and fasted gerbils,
but reversed absorption into secretion in the jejuna from
undernourished gerbils. In the ilea taken from fed animals the
small basal absorption was reversed to secretion by luminal
cGMP. Although cGMP produced no significant changes in fluid
secretion in the ilea taken from fasted gerbils, yet it caused a
significant increase in those from undernourished gerbils. In
the colon taken from fed animals cGMP decreased the basal fluid
absorption significantly, but it had no significant effect on
fluid secretion in the colon of fasted or undernourished
gerbils. We conclude that fasting and undernourishment have no
significant effects on fluid transport across the gerbil jejunum
but reversed basal absorption in the fed ileum and colon into
secretion. cGMP mimic the effects of STa in the jejunum taken
from undernourished gerbils, in the ileum obtained under the
three nutritional states and in the colon taken from fasting
animals.
Key words
Gerbil Ileum Jejunum Starvation Undernourishment
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