Labeled glycine of collagens of different-aged normal and cortisone-treated rats

¹ Division of Dermatology, University of Minnesota Medical School, Minneapolis, Minnesota

Injections of glycine-2-C¹⁴ into control and cortisone-treated weanling, young adult, and adult male rats were followed by determination of the specific activity of glycine from citrate-soluble and mature skin collagen and total femur collagen. The time for the specific activity of glycine from citrate-soluble collagen to decrease to that of glycine from mature collagen increased with increasing age. Faster metabolic turnover of femur collagen than skin collagen was indicated in each group of control rats. Synthesis of collagen under conditions of constant collagen content was indicated in adult rats by incorporation of radioactivity into skin and femur collagen. Cortisone treatment resulted in significant changes in the specific activity of collagen glycine only in weanling and young adult rats. In cortisone-treated rats, significant changes in the specific activity of glycine from mature skin collagen were less prominent than, and were associated with, changes in total skin collagen, but significant changes in the specific activity of glycine from femur collagen were more evident than, but not always associated with, changes in quantity of femur collagen.

Key Words: skin collagen metabolism • femur collagen metabolism • connective tissue

Submitted on March 15, 1963