Increased glycation and pigmentation of collagen in aged and young parabiotic rats and mice.

Changes of non-enzymatic collagen glycosylation were followed in 2- and 24-month-old rats and mice and in parabiotic animals of the same age. With advancing age increased glycation of collagen was observed in both old male Wistar rats and white mice. Further it was demonstrated that both aortal and skin collagen of young animals is rapidly non-enzymatically glycosylated in the common milieu created by parabiotic animals and the proportion of non-enzymatically incorporated glucose approaches in the young counterparts the level found in old individuals. Similar trends as with non-enzymatic glycosylation were found with a fluorescent (370/440 nm) product present in both categories of collagen preparations. This fluorescence was higher in old animals and was considerably increased in the young counterpart of the parabiotic couple 6 weeks after operation. The nature of the fluorescent product appears different from pyridinoline and remains to be elucidated.