The uptake of (35S) sulphate by mucopolysaccharides of granulation tissue

Authors:
  • EKEgon Hynek Kodicek
    Egon Hynek Kodicek
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Abstract
In order to gain some insight into the formation and fate of the sulphated polysaccharides of granulation tissue, the (35S) sulphate uptake of regenerating tendons of guinea-pigs was determined in vivo. Hexosamine and hydroxyproline contents were estimated at various stages of healing. The maximum 35S uptake occurred after the seventh day and was maintained for at least 8 more days, returning to low values on the 23rd day after operation. The relationship between sulphate uptake, hexosamine and hydroxyproline contents was determined and discussed. In scurvy, the uptake of 35S was lower than in controls, while hexosamine values were unchanged. This was presumed to indicate that though the total amount of polysaccharide in scorbutic granulation tissue was undiminished, it was not sulphated in the normal way. A polysaccharide component, which was highly radioactive and had a mobility of approximately the same order as chondroitin sulphate, was separated from normal granulation tissue by extraction and ionophoresis on paper. It was thus shown that sulphation of a mucopolysaccharide was responsible for the uptake of 35S. The mechanism of (35S) sulphate uptake was studied in vitro by incubating slices of granulation tissue in a medium containing radioactive sulphate. Disruption of cells by homogenization or freezing-and-thawing greatly reduced the incorporation of sulphate. Little or no uptake of 35S occurred in boiled tissue, in the cold, or in the absence of oxygen. 2:4-Dinitrophenol, azide, cyanide and certain sulphydryl-binding substances were found to inhibit the reaction. Salicylate caused an inhibition, while cortisone had no such effect. Scorbutic granulation tissue showed a decreased fixation of sulphate. It was concluded that sulphate uptake by granulation tissue was dependent on an enzymatic reaction, possibly involving oxidative phosphorylation.