Metabolism of collagen. Appearance and disappearance of [14C]hydroxylysine in rat connective tissue

Abstract

Collagen metabolism was studied in developing connective tissue of the adult rat by sponge-implantation and labelling with [C14]hydroxylysine. Labelling by the intraperitoneal administration of [Cl4]lysine reached its maximum serum concentration within 15 min. Young connective tissue characteristically synthesized a large amount of labile collagen. Stable collagen was formed either as a part of the labile-collagen synthesis or independently. The stable form was constant in amount at 8, 12 and 20 days'' tissue age and remained in the tissue for weeks. The labile form of collagen was synthesized only during the early period of connective-tissue formation. At 20 days, synthesis of this form was not detected. The metabolism of collagen was influenced by sex. Isotopic studies indicated a more active synthesis and the formation of larger amounts of stable collagen by the cells of the male. These characteristics should effect a greater accumulation of collagen in the tissue from the male.