[A mathematical model of the kinetics of collagen metabolism in the tendons and skin of young and old rats].

Two groups of 60 male Sprague-Dawley rats aged 3 and 20-24 months respectively were used to establish a 3-compartmentmodel of the kinetics of the collagen metabolism in the tail tendon and skin by means of tritium labelled L-prolin. The 3 compartments were divided into pro- and tropocollagen, labile polymer collagen and stabile polymer collagen respectively. The results suggest the following conclusions concerning the metabolism and ageing of the collagens investigated: 1. Collagen of the tendon and collagen of the skin reveal different dynamics of metabolism. 2. Stabile and labile polymeric collagen originate from different tropocollagens. 3. Both intracellular and extracellular processes are responsible for the age-changes of tendon- and skin-collagen.