Connective Tissue V. Comparison of Synthesis and Turnover of Collagen and Elastin in Tissues of Rat at Several Ages. ∗

Summary

1. Synthesis and turnover of collagen and elastin was studied in rats of 5 weeks, 8 months and 2 years of age, respectively, by observing incorporation and removal of uniformly labeled C¹⁴-lysine. 2. Synthesis of collagen and elastin was more rapid in the tissues of young rats (5 weeks) than in those of older animals. In tendon, no detectable synthesis of IC was found at 2 years of age. 3. The uterus was the only organ examined, which showed appreciable synthesis and turnover of collagen in older animals. 4. The turnover rate of collagen in relation to other proteins was low in all animals even in those 5 weeks old. No turnover was observed in the insoluble collagen of tendon and skin at 8 months and 2 years of age, respectively.