T he effects of X -rays on the uptake of radioactive sulphate

Radioactive sulphate (35S04) is readily taken up and ‘fixed’ by cartilage, from which it can be extracted in chondroitin sulphate (Bostrom & Mansson 1953). In autoradiographs the isotope is found at sites where acid mucopolysaccharides are formed (Curran & Kennedy 1955). Sulphate is incorporated into the muco­ polysaccharide molecule at an early stage in its synthesis (Schiller, Mathews, Cifonelli & Dorfman 1956) and ion exchange is not involved. Sulphate uptake may be used therefore to measure sulphated mucopolysaccharide formation (Layton 1951; Slack 1959). In the present study, the effects of X-rays on the sulphate uptake of mouse tissues and of calf costal cartilage were determined by autoradiography and by means of a Geiger-Muller counter, respectively. In this way it was hoped to gain some information concerning the effects of ionizing radiation on mucopolysaccharide secretion, about which little is known.