Age- and feeding-dependent production of carbonyl compounds in hypoxic heart. The role of carbonyls produced in connective tissue modification.

The concentration of reactive lipid metabolites (malondialdehyde, formaldehyde, acetaldehyde and acetone) was assayed in rat heart reperfusates after 30 min ischemia in animals of different age and kept on different feeding regimes. It was revealed that there is no difference in the concentration of reactive carbonyl compounds in reperfusates from animals of different age, but the amount of released carbonyl compounds is much lower in animals kept on 50% restricted diet. If tail tendons from young (3 months) rats are incubated in the reperfusate, their solubility after CNBr treatment is decreased so that this material resembles tendons from old animals. Also the amino acid composition of the insoluble residue cannot be distinguished from that obtained from rat tail tendons of 24- or 29-month-old rats. The results prove the ability of carbonyl containing lipid metabolites to create a CNBr-insoluble core in connective tissue.