AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 2 177-G183, Copyright © 1985 by American Physiological Society
Effect of ethanol on choline transport in rat jejunum
J. J. Hajjar, E. R. Baker, D. M. Renison, P. W. Gardner, R. Zirin and T. K. Tomicic
The effect of ethanol on choline transport across the rat jejunum was
studied by intraluminal perfusion in vivo and by influx measurement across
the brush-border membrane in vitro. Acute ethanol administration (4 g/kg)
through a gastric tube caused an increase in net choline absorption within
1 h. The increase was prevented by pretreatment with pyrazole, an inhibitor
of ethanol metabolism. Chronic ethanol administration also caused an
increase in choline absorption, the effect being unrelated to the
nutritional changes that occur with ethanol ingestion. In contrast, direct
instillation of 0.65 M ethanol through the perfusate caused no changes in
choline absorption, and the perfusion of a 1.14 M solution even decreased
absorption. The in vitro influx of choline across the mucosal membrane of
the isolated rat jejunum was also enhanced by pretreatment with ethanol
given by gavage 1 h prior to experimentation. Similarly, the
ethanol-related increase in the influx rate was inhibited by pyrazole but
was unaffected by acetaldehyde or acetate. Like ethanol, pretreatment of
rats with methanol stimulated the choline influx rate. The results suggest
that ethanol metabolism, rather than the direct effect of ethanol by
itself, stimulates the absorption and influx of choline into the rat
jejunum. The effect is not produced by the primary metabolites of ethanol,
acetaldehyde, or acetate but is very likely related to stimulation by other
products of ethanol metabolism.
