Collagen Synthesis and Degradation In Vivo. Evidence for Rapid Rates of Collagen Turnover with Extensive Degradation of Newly Synthesized Collagen in Tissues of the Adult Rat

https://doi.org/10.1016/S0174-173X(87)80001-8Get rights and content

Abstract

Collagen turnover is now known to occur more rapidly in body tissues than traditionally believed, but the kinetics and mechanisms for degradation are still poorly understood. Here we measure collagen synthesis rates and the proportion of newly synthesized collagen (probably procollagen) which is rapidly degraded, in tissues of the adult rat after injection of [14C] -proline with a large “flooding” dose of unlabelled proline. Incorporation of [14C]-proline into lung, heart, skeletal muscle and skin collagen and its appearance as hydroxy [14C]-proline, free or in small molecular weight moieties, at various times up to one hour, suggested extremely rapid synthesis and degradation for some tissues of the adult rat. Values in heart, lung, skeletal muscle and skin (with the proportion of degradation of newly synthesized collagen shown in parentheses) were 5.2±0.7%/day (53±5%),9.0±0.7%/day (37±2%),2.2±0.3%/day (38±7%) and 4.4±1.3 %/day (8.8±0.5 %). These data provide in vivo evidence, which are consistent with the observation in isolated cells, that a proportion of newly synthesized collagen is degraded rapidly, and probably intracellularly, after its synthesis. They also indicate that collagen may be synthesized and degraded rapidly in normal rat tissues, but the mean turnover rates and the proportions of collagen degraded intracellularly vary widely between tissues.

References (39)

  • SodekJ.

    A comparison of the rates of synthesis and turnover of collagen and non-collagen proteins in adult periodontal tissues and skin using a microassay

    Arch. Oral Biol.

    (1977)
  • ArmitageP.

    Statistical Methods in Medical Research

  • AvioliL.V. et al.

    Collagen degradation and the response to parathyroid extract in the intact rhesus monkey

    J. Clin. Invest.

    (1967)
  • BarnesM.J. et al.

    Studies in vivo on the biosynthesis of collagen and elastin in ascorbic acid-deficient guinea-pigs

    Biochem. J.

    (1970)
  • BergR.A. et al.

    Lysosomal function in the degradation of defective collagen in cultured lung fibroblasts

    Biochemistry

    (1984)
  • BienkowskiR.S.

    Intracellular degradation of newly synthesized collagen

    Collagen Rel. Res.

    (1984)
  • Bienkowski, R. S., Morton, J. C., McDonald, J. A. and Crystal, R. G.: Degradation of newly synthesized collagen. J....
  • BienkowskiR.S. et al.

    Fibroblasts degrade newly synthesized collagen within the cell before secretion

    Nature

    (1978)
  • DehmP. et al.

    Biosynthesis of Cartilage Procollagen

    Eur. J. Biochem.

    (1973)
  • Cited by (0)

    2

    Dr. R. J. McAnulty, Biochemistry Unit, Department of Thoracic Medicine, Cardiothoracic Institute, University of London, Fulham Road, London SW3 6HP

    View full text