[Age peculiarities in the content of nucleic acids, collagen (as oxyproline) and other proteins in rat skin and lung tissues].

It is established that in old animals, as compared to the young ones, the content of nucleic acids, the total content of protein and the content of the peptide-bound oxyproline in the collagen soluble fractions in the skin and lungs tissues decrease, whereas the content of peptide-bound oxyproline in the insoluble collagen and of free oxyproline, vice versa, increases.