Age-related changes in the content of fibrous proteins in the rat tissues.

An attempt was made to establish a relationship between the content of elastin and collagen in the rat tissues during the process of aging. The content of collagen fractions and elastin in the rat liver, lung and skin, as well as the elastolytic activity of blood serum were determined. It was found that the concentration of elastin as well as the elastolytic activity of blood serum are increasing during the maturation of rats and the total collagen content is increasing too. After the animals reached the age from twelve to twenty four months--above mentioned values began to decrease. It is concluded that the changes in the content of the two fibrous proteins of the connective tissue depend on age.