First-pass metabolism of ethanol is negligible in rat gastric mucosa.

Controversy exists concerning whether first-pass metabolism of imbibed ethanol occurs in the gastric mucosa or liver. We assessed ethanol metabolism in rat gastric mucosa by determining to what extent intact [14C]ethanol in body water plus hepatic metabolism could account for [14C]ethanol absorbed from the pylorus-ligated stomach. Intact [14C]ethanol in systemic body water accounted for 84 +/- 1.9% of the [14C]ethanol absorbed from the stomach over a 30-min period. Assuming a 15 ml/min hepatic blood flow, the predicted hepatic metabolism of [14C]ethanol over the 30 min of the study was 18% of the dose. The sum of intact [14C]ethanol and predicted hepatic metabolism accounted for 100% of the ethanol absorbed from the stomach. We conclude that negligible metabolism of ethanol occurred in the gastric mucosa.