To examine the relation between ethanol-induced microvascular and absorptive changes, we have investigated the effect of 16,16-dimethyl prostaglandin E2 on the jejunal intraluminal plasma albumin loss (which was taken as a measure of microvascular changes) and the inhibition of water, sodium, and glucose transport caused by intraluminal ethanol. A group of 8 dogs received intravenously 16,16-dimethyl prostaglandin E2 at a dose of 0.1 microgram/kg as a bolus followed by 0.05 microgram/kg.hour for 2 h (prostaglandin-treated group). A second group of 8 dogs received no 16,16-dimethyl prostaglandin E2 (untreated group). In each dog of both groups, one jejunal segment was perfused with an ethanol-free solution (control segment) and an adjacent segment was perfused with the same solution containing 6% (wt/vol) ethanol (ethanol-perfused segment). The albumin loss (mg/g dry gut wt.90 min, mean +/- SE) by the control and the ethanol-perfused segments was 0.76 +/- 0.23 and 8.29 +/- 1.27, respectively, in the untreated group, and 0.66 +/- 0.23 and 4.81 +/- 0.67, respectively, in the prostaglandin-treated group. The ethanol-induced increase in albumin loss was significant in both groups, but was significantly lower (p less than 0.05) in the prostaglandin-treated group than in the untreated group. Intraluminal ethanol depressed net water, sodium, and glucose transport by 74%, 52%, and 22%, respectively, in the untreated group, and by 92%, 65%, and 38%, respectively, in the prostaglandin-treated group. The magnitude of this depression did not differ significantly between the two groups. As 16,16-dimethyl prostaglandin E2 attenuated the ethanol-induced plasma albumin loss, but not the inhibition of water, sodium, or glucose transport, we conclude that the microvascular and the absorptive changes produced by ethanol are not mediated by the same mechanism.