A comparative study of ethanol absorption in the canine jejunum after pretreatment with cyanamide or pyrazole.

This report describes the retardation of ethanol absorption from the intestinal tract and reduction of portal blood flow by high acetaldehyde concentrations in dogs using a jejunal segment with the vascular supply intact. The cyanamide-pretreatment group (CY), in which an extremely high acetaldehyde concentration developed, in comparison with the control and pyrazole-pretreated (PY) groups, showed a gradual increase of portal blood ethanol, a 25% reduction in the amount of absorbed ethanol, and an 85% smaller absorption rate constant value (Ka). These facts indicate that the presence of a high acetaldehyde concentration in the blood results in a reduction of ethanol absorption and retardation of ethanol reaching the systemic circulation. The rapid reduction of portal blood flow and the lower ethanol level in the portal vein observed in the CY group, in comparison with the other two groups, also indicate that the reduction of ethanol permeability through the absorption site to the blood is an important retarding factor induced by acetaldehyde.