[Peptidomes of the brain, heart, lung, and spleen of a rat: similarity and differences].

Profiles of endogenous peptides of the brain, heart, lungs, and spleen of a rat have been obtained by chromatographic and mass spectrometric analysis of low-molecular-mass fractions of tissues extracts. The concentrations of the corresponding components have been estimated from the intensities of 119 major chromatographic peaks. The total content of peptides in tissues, nmol/g (mg/g), was 3-13 (0.005-0.05) for the brain, 7-27 (0.01-0.10) for the heart, 17-68 (0.02-0.25) for the lungs, and 80-300 (0.08-1.30) for the spleen. A comparative analysis of the data obtained for the organs has been performed. The primary structures for 68 peptides have been determined; most substances (>70%) have been identified as hemoglobin fragments. It has been shown that many of the peptide components identified (>75%) are common for several organs. The relationship between the composition, the mechanism of formation, and the functional role of peptidomes of the organs, tissues, and cells of higher organisms has been discussed.