[Content of collagen fractions and synthesis of collagen in lung tissues of rats of various ages].

The content of soluble fractions and biosynthesis intensity of collagen were studied by means of 3H-proline incorporation into the lung tissues of different-age rats. The method with incorporation of a radioactive label is shown to detect more clearly the age peculiarities in collagen metabolism. The most considerable decrease in the intensity of 3H-proline incorporation into lung collagen is observed during the first four months of the rat life.