Role of intestinal bacterial overgrowth in ethanol production and metabolism in rats

Gastroenterology. 1986 Jan;90(1):103-10. doi: 10.1016/0016-5085(86)90081-8.


To investigate the role of intestinal bacterial overgrowth on the production and metabolism of ethanol, rats with a jejunal self-filling diverticulum (blind-loop) were compared to controls with a self-emptying diverticulum. Both endogenous ethanol and acetaldehyde were found in the blind-loop contents. Intragastric administration of sucrose produced a marked increase in acetaldehyde and acetate in the portal venous blood, with only a modest elevation of ethanol. Blind-loop contents readily oxidized ethanol to acetaldehyde in a concentration-dependent manner and more actively under aerobic than anaerobic conditions. This oxidation was inhibited by antibiotics and was reproduced with isolated microorganisms. Intragastric administration of ethanol to rats with blind-loops markedly increased acetaldehyde and acetate concentrations in the portal vein and, to a lesser extent, in the systemic blood, compared with the controls. By contrast, both portal and systemic blood ethanol concentrations were lower in the rats with a blind-loop compared with controls, even though the amounts of ethanol retained in the digestive tract were similar. A dose of ethanol about twice as large as in controls was required to produce similar systemic blood levels. Both in rats with a blind-loop and in the controls, the areas under the curve of blood ethanol concentrations were smaller after intragastric than after intravenous ethanol administration (1 g ethanol/kg body wt). This difference was exaggerated in the rats with a blind-loop. Thus, a considerable amount of ethanol is oxidized in the gastrointestinal lumen of rats with a blind-loop. The resulting high concentrations of acetaldehyde, both in the intestinal lumen and the portal blood, may have deleterious effects on the gastrointestinal mucosa and the liver.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetaldehyde / blood
  • Acetaldehyde / metabolism
  • Animals
  • Bacteria / metabolism
  • Blind Loop Syndrome / metabolism*
  • Ethanol / administration & dosage
  • Ethanol / blood
  • Ethanol / metabolism*
  • Jejunum / metabolism
  • Jejunum / microbiology*
  • Male
  • Oxidation-Reduction
  • Rats
  • Rats, Inbred Strains
  • Sucrose / pharmacology
  • Time Factors


  • Ethanol
  • Sucrose
  • Acetaldehyde