Abstract
A simple and reliable method for quantitative assessment of autoradiographs by comparative histophotometry has been described. Its application to the study of tissues tagged in vivo with S35 methionine or S35 sulfate, and after Ca45 in vitro uptake, has revealed regional differences in the synthesis of proteins and sulfated mucopolysaccharides, as well as in the residual amount of cation binder present in cartilage of normal growing rats. It has also revealed differences in the behavior of all three materials between normal and magnesium deficient animals.