Blood plasma peptides of rats after administration of ethanol or acetaldehyde.

The blood plasma peptide fractions labelled with 3H-leucine after chronic administration of ethanol or acetaldehyde in rats have been analysed. Total 3H-leucine radioactivity in peptide fraction calculated per millilitre of plasma in both study groups was significantly decreased. The amount of peptide spots obtained by tlc in the ethanol-treated group or acetaldehyde-treated group was reduced in comparison with the control group. Analysis of amino acid composition of atypical spots occurring in both test groups revealed the presence of aromatic amino acids and methionine, but was associated with the absence of branched-chain amino acids, such as valine, leucine and isoleucine. These findings suggest a change in protein metabolism in hepatic dysfunction in rats receiving ethanol or acetaldehyde.