Effect of Age on the Heparin Content of Rat Skin

IN 1955, Shetlar and Masters1 demonstrated a change with age in the composition of acid mucopolysaccharides of human cartilage. They found that both uronic acid and hexosamine decreased with age but the decrease in hexosamine was less striking, indicating a relative increase in some hexosamine-containing polysaccharide. Further evidence for a shift in the relative proportions of acid mucopolysaccharides in ageing cartilage was provided by Kuhn and Leppelmann2, who reported a decrease in the ratio of galactosamine to glucosamine. Recently, Kaplan and Meyer3 observed that the content of chondroitinsulphuric acid in human cartilage decreased and that of keratosulphate increased with age. On the basis of an increasing glucosamine to galactosamine ratio, Hallen4 concluded that the ratio of keratosulphate to chondroitinsulphuric acid in human nucleus pulposus increased with age. A difference in the distribution of mucopolysaccharides between embryonic and mature pig skin was reported by Loewi and Meyer5. They found that hyaluronic acid comprised 78 per cent of the total skin mucopolysaccharides in the embryo and only 30 per cent in the adult, whereas chondroitinsulphuric acid-B represented 5–12 per cent in embryonic skin and 64 per cent of total mucopolysaccharides in adult skin.