Increased ethanol consumption and blood ethanol levels in rats with portacaval shunts.

In a series of experiments, it was demonstrated that male rats with end-to-side portacaval shunts (PCS) consumed more ethanol and exhibited higher blood ethanol levels than sham-operated control animals in chronic tests with 2% ethanol and water ad libitum. Ethanol intake in the 6 h prior to blood sampling was 2-5 times and blood ethanol 10-50 times higher in PCS than control rats. These effects were not due to the feminization of male rats occurring after a PCS, since female PCS rats exhibited comparable increases of ethanol intake and blood ethanol. In both sexes ethanol elimination rate and alcohol dehydrogenase activity per total liver were lower after PCS than in control rats, explaining the disproportionate increase in blood ethanol relative to ethanol intake. Interestingly, ethanol intake was not abnormal in PCS rats fed a low-protein, low-tryptophan diet (corn) alone or as a supplement to the usual chow diet. Such dietary modulation of ethanol preference in this animal model of chronic liver dysfunction merits further attention.