The role of
folate deficiency in the pathogenesis of the abnormalities of structure and transport of the small intestine that are often present in certain disorders such as
alcoholism is unclear. One reason for this is that the
folate status of the intestinal mucosa has never been ascertained in humans. Previous investigations have shown that a deficient diet supplemented with sulfa does produce
folate deficiency of the intestinal mucosa in weanling rats and that this is associated with
diarrhea and structural abnormalities of the jejunum. In the present study, we used then in vivo marker perfusion technique to examine the jejunal transport of water,
sodium,
xylose, glucose, and
L-leucine in such
folate-deficient rats. Supplementation of the normal diet with sulfa did not produce
folate deficiency of the intestinal mucosa, but it was associated with a moderate reduction in water absorption; this was attributed to cecal enlargement in these rats. Rats placed on a
folate-deficient diet plus sulfa developed markedly depressed serum and jejunal
folate concentrations, net secretion of water and
sodium, and persistent
diarrhea; absorption of
xylose, glucose, and
L-leucine remained normal, however.
Folate repletion of these rats by water and
sodium transport to absorption ano cessation of
diarrhea. These observations indicate that
folate deficiency of the intestinal mucosa alters the transport of water and
electrolytes but not that of such solutes as
xylose, glucose, and
L-leucine. They suggest that when transport abnormalities of these solutes occur in
folate-deficient alcoholics, this in not due to the
folate deficiency but rather to other pathogenic factors such as
ethanol.